That One Boss/Strategy

NOTE: Bonus Boss, Final Boss and Wake Up Call Boss cannot be That One Boss without being overly hard by their standards. Please do not nonchalantly add them as examples.

Nintendo Wars

 * In the original Advance Wars, the final battle against Sturm is considered very difficult compared to the rest of the game, especially if you want to S-Rank. If you can get past that, and get used to the difficulty of the Advanced Campaign, the secret final battle against Eagle, called "Rivals", is known to make grown men cry. The Advanced Campaign version of "Kanbei's Error?" transforms a rather easy level into one that's borderline impossible to beat unless you follow a very specific set of steps.
 * Advance Wars 2 has TWO That One Boss maps: the giant missile launcher and the Black Hole factory in Blue Moon. Augh. Augh. Augh. Augh. AUUUUUUGH.
 * It gets worse. "Sinking Feeling", the final mission in Green Earth, and any mission against Sturm are magnitudes harder.
 * Hardest mission of all in Advance Wars 2? "Liberation" Hard Campaign. Sure let's give the AI a machine that spams free bombers and neotanks without giving the player any time to prepare.
 * Days of Ruin/Dark Conflict has several including the tower mission, both missions where you're being bombed by the Great Owl, the mission ON the Great Owl, and the final mission to players who only ever get by by spamming war tanks and bombers.
 * The mission ON the Great Owl is an interesting case. Its very easy, once you know what to expect and move to counter it. The first time through, you have NO idea that no less than THREE waves of reinforcements are gonna pop, reinforcements that include things like Rocket Launchers and Light Tanks, coming from BOTH sides of the map.
 * And the final mission in Days of Ruin is about three times harder than any other mission in the entire series if you don't use a day-by-day walkthrough. Your enemy gets to crank two free units of whatever he wants every day, laser beams that fire everywhere, two mortar launchers that fire daily at a group of your units, and the ability to turn one of his own units into a superunit that makes all other units in a radius super-powered as well and heals them 50% of their HP every turn. Most players, if they concentrate solely on the objective, can take out four of the mission targets before the enemy starts completely annihilating them and preventing them from reaching the last target.
 * "Waylon Flies Again", notoriously, can't have a day-by-day guide - Waylon's AI is impossible to map out. You have a fucking mountain range between you and Waylon's forces, he starts out with a substantial property-and-unit advantage, and while Tasha brings in a nice arrangement of anti-air, it's blunted by how you lose if she's wiped out. Being able to take control of and flood the middle area of the map with your own units will tilt the odds in your favor, but it's an uphill struggle.
 * Battalion Wars is quite easy up to one level. It's where you have to defend a beach, very much like beachhead. You have limited troops, four mounted machine guns (more useless, when you get to the flamethrower rounds), two artillery, and one heavy recon. The first two waves are relatively easy. Wave one is foot troops. Wave two is foot troops AND tanks. Simple. The enemy then freaks out and another person joins the fight. The enemy air general. Who joins up with the enemy foot person with bombers and rocket troops. Your general's suggestion? ONE AA VEHICLE. ONE. Did your friendly vehicles suck up all of the vehicle health kits? Yes? Prepare to be sent back to the mission failed screen in about 2 minutes.
 * Except that part of the mission can be made ridiculously easy. Let me guess: you lose quite a few units during the first two parts? Guess what? 100% Technique on that missions requires no losses whatsoever.
 * Dual Strike has a level where you're trying to destroy one of those crystal things, only this time it's the last one and it's huge. Let's set up the scenario, shall we? You start off with two different bases, both near each other on opposite sides of a pipeline. Remember those cannons Black Hole built to protect said pipes? Yeah, there are at least two of them. There's also a great big cannon at the top of the map that fires at any unit that crosses into its cone-shaped firing area. Not to mention the Kill Sat that fires every five turns after its reveal, and you have to commandeer missile silos to take it down. If Black Hole takes any of these silos, you lose. Period. Then there's the fact that the crystal in the center of the map keeps healing their units, and they keep coming at you with more and more powerful stuff because they control most of the cities on the map. Unfair? YES.
 * The 'Surrounded!' Mission isn't too much of a problem on Normal, but it quickly becomes the hardest mission in the campaign on Hard Mode. Not only do you have smaller bases than before, but the enemy has a much larger one than your 2 bases combined. And while the mission has a Turn Limit of 24, you will often die around Day 4 when the enemy decides to use their Tag Power, which is a huge problem because they get to use Andy. Even using CO's with Capture+ Skills (as this is a capture based mission) wont help you, as the AI will randomly do something that makes the mission impossible to win.

Super Robot Wars

 * Dark Brain in Super Robot Wars Original Generation Gaiden, who so happens to be the Big Bad of the game, but not the Final Boss. Needless to say, if you don't readily prepare yourself with the SP Regeneration Pilot Skill for the characters... well, you'll have to chip away at his HP when he enters One-Winged Angel, gaining twice the amount of HP his first form has (meaning, you're fighting a boss that has an accumulated total of ONE MILLION) that regenerates one-third of it every turn. Not to mention before fighting him, you'd have to fight several extremely strong Elite Mooks that almost equal many previous sub-bosses. Did we mention that if any of your pilots are unlucky enough to get hit with his attacks, even when fully upgraded, a One-Hit Kill is certainly guaranteed? Arguably, due to Dark Brain's high-end HP, rate of regeneration, the existence of a second form, high armour rating and devastating attacks, he's become a standout example for the ENTIRE franchise, a feat not seen since Super Robot Wars Alpha Gaiden.
 * And in Original Generation 1, there's R-Gun Rivale: A mech that has more than 100000 hp (estimated to be about 150000, but until reduced to below 99999 HP is shown as ?????), has a very, very powerful main attack, an only slightly less powerful secondary attack (with ammo so high it may as well be infinite), and a tough melee attack that uses neither EN nor ammo. It has a ton of EN with which to power its main attack and its damage-halving shield, which regenerated each turn. Oh, the health regenerates too. Couple this with the pilot's uncanny aim, and most real robots without mobility increasing parts will go down in one shot, while your super robots' attacks bounce merrily off his shield. To make matters worse, unlike the boss battles afterwards, the fight against the Rivale doesn't give you many places where you can regain health or energy, if any at all.
 * To make matters worse, the Original Generation games have Battle Masteries, some of them requiring you to defeat them in as few as seven turns for the fight against the Rivale. And the Combining Mecha that you get access to when you reduce its health to a certain level not only lacks the power to do very much to the R-Gun Rivale, even when spamming spirit moves, but also only lasts three turns and burns like a torch when tagged with the Rivale's Gun Slave and Axiom Buster omnideath guns (that are its standard ranged weapons). Oh, and the SRX's best move? It's melee. So it won't even use up any of that Gun Slave ammo.
 * Also keep in mind you have to fight that damn thing TWICE and the first time you don't even see it coming as it's hidden in the regular R-Gun.
 * The fight against Bian Zoldark in Original Generation 1. Compared to the R-Gun Rivale, Judecca, and other end-game mechs, Zoldark's Valsion is profoundly inferior. However, it still has a damage-halving barrier, a massive store of energy to fuel the barrier, attacks that, at that point, are downright broken, and the fact you have to hack through hordes of enemies to get to it. You also have to fight an even stronger mech and beat it before going after Zoldark to get the Battle Mastery, all while Zoldark gets to deliver potshots at you. And unlike fighting the Rivale and other enemy units, you have only ONE energy-reducing weapon, which must be reloaded every two shots-- and heaven help you if you didn't equip someone with the Resupply Module, because then you can't reload it at all. And to clinch it, at that point in time, very few people will have SP Regain, meaning you must ration off Spirit commands all but necessary so as to evade the Valsion's attacks.
 * OG 2's Inspectors show up early on, when your units levels and numbers are still fairly low. They all have over 100,000 hit points and are healed by beam weaponry. Thankfully, they don't need to be defeated until near the end... unless you want to get some bonus items and a cool little No Fourth Wall moment.
 * Wilhelm von Juergen and his Valsion Custom CF in OG Gaiden may also count (the bonus section of Original Generations treats him as a final boss, so he didn't count back then). He appears after you have fought hordes and hordes of Bartolls, ones with crazy dodge rates (which to be honest, if done without your Seishin points, it's very hard, especially if you're not beefed up as you see them in the latter periods, whereas they are somewhat of a joke), then also pitting you with a Brainwashed and Crazy Lamia (no Angelg for you) and a victory condition which demands Kyosuke to be the one to beat her (almost impossible without sacrificing some seishin points). Then he comes with around 300k HP to your drained party, still dodges quite good, and you probably haven't upgraded your mechas very much (either you are saving for a bigger investment like Folka, or the fact that your POV jumped forth and so on in the previous scenarios, making upgrades and Pilot Points sparse, you might not get someone with SP Regen this way). And then, just to rub it in, he commits a Player Punch by "killing" Lamia (thereby, not letting her be a reinforcement: ) before even starting the battle, and any remaining Bartolls might still be around to harass you further. How is THAT for a That One Boss?
 * SHUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU!! Shirakawa and his Neo Granzon in Super Robot Wars Alpha Gaiden was the hardest boss in Super Robot Wars history, until Dark Brain dethroned him. Like the latter, the Neo Granzon also goes One-Winged Angel (hence "Neo"), can regenerate HP to full again and again for both player and enemy phases, gets an extra turn for every round AND will use it for two MAP Attacks, which hurt like a bitch and may as well destroy all allied units on the field. And it also happens to be ungodly powerful, with an attack called Shukutaihou. This attack in all of Neo Granzon's appearances almost ALWAYS guarantees a One-Hit Kill, and only those with exceptionally high armour ratings (re: Super Robots) can have a chance to SURVIVE. To give a better picture of this, in an earlier game with the Neo Granzon, the Shukutaihou's base damage is 19400, a number even higher than the Final Boss' HP. If you get hit... well, let's just say whatever's left of the unlucky target won't even fill a coffee can.
 * Gym Ghingham in Alpha Gaiden is also a real bastard on hard, especially considering how if you want to speed kill the bastard for battle mastery, you have to haul ass for him, ignore the Elite Mooks, and pray you can kill his Zalbak guards, then ice the SOB. Just to screw with you, he regenerates his HP and Energy at least once, and you have a ten turn time limit (and three will be spent just getting to him!) How quickly you take Gym out depends on how much SP you have left after getting through all that.
 * Don't forget Alpha Gaiden's Emperor Gore. He regenerates up to SIX Times and has mile high HP. Asshole just REFUSES TO DIE!
 * Alpha 3 has Muge Zorbados. By himself, he's not that bad. Unfortunately, he's fought on a Real Robot route, thus greatly crippling your ability to deal out tons of damage and use supers to soak up hits. Second, you have to fight a huge assortment of enemies, at least a full third of which are boss level in their own right. Third, one of them mind controls part of your team from the get go, forcing you to make killing his ass a priority. Finally, after having pissed away most of your seishins dealing with the boss horde, Muge Zorbados himself has a considerable chunk of HP and can do a nice amount of damage, mostly likely killing off most of your weaker troops, and most of your stronger troops will be scraping the bottom of the barrel for ammo by this point-- assuming the horde of bosses haven't killed all your supply mecha yet.
 * GODDAMN FARAH!!! Super Robot Wars D is more known for the collective hordes of evil out for your blood that invert the Sorting Algorithm of Evil, where most of the bosses are small fry compared to the Original Generation mooks. Except Farah. Goddamn, goddamn Farah. She's in a small machine (hard to hit), laden with four items to boost up her accuracy and dodge rates, her machine has thicker armor than a Real Robot-style mech should ever, EVER have, and you fight her after one of the most grueling levels in the game. It doesn't help that aside from the Original Generation mooks, the Victory Gundam ones are the Demonic Spiders of the game. Farah is the pinnacle of that mind-numbing terror, laughing off the best attacks as your Spirit Points dwindle to nothing, your oft-praised and perfect aces humiliated time and time again by this single woman when they can't shoot her down. And that's BEFORE Prevail kicks in. For those not in the know, the "Prevail" skill raises a unit's parameters as its HP goes down (especially defense), so smack Farah down to her last bit of health, and her threat level goes from "really dangerous" to "will completely and utterly wreck your shit".
 * Try the Mission where you have to prevent the Adrasteas from progressing to the other end of the map, and make sure that they are not destroyed (Have to weaken them to a certain HP level), Not to mention the Reinforcements that arrive (Another Fucking Adrastea and more mooks). You practically have to use your own units to box them in to prevent them from advancing.
 * The final battle map in Super Robot Wars Destiny is aggravating for one reason. Before you fight the Final Battle, you have to fight two Original Generation bosses, who will always recover their full HP unless you kill them in one shot from around the half HP mark, and have considerably high HP... coupled with the fact that if your machine can do enough damage to them to kill them, they will enter the battle in defence mode and cut your damage in half. Effectively, you're forced to go into the battle doing enough damage to almost kill them, and have another unit support your unit to finish them off, as they won't factor support attacks in to whether they defend or not... and support attacks do half damage on their own.
 * The absolute worst boss in SRW D would have to be Gepelnitch, however. 200,000 HP, with one shot of full recovery once he hits 100,000 HP, with a skill on top of that which halves all damage done to him except that done by song weaponry, which runs out quickly and cannot be resupplied aside from a meagre pittance of per-turn regen. Which doesn't come anywhere close to Gepel's per-turn HP regen. Alternately you can drain him of will to disable his damage-halving skill, but after two or three attacks he will have gained enough to turn it back on rendering your attempt meaningless.
 * Master Asia in Super Robot Wars Advance. A tough opponent to hit at the best of times and will regenerate infinitely unless you knock him down from approximately half his health to nothing in a single attack. If you don't have someone with Valor it's definitely one of those easier-said-than-done things. There's a reason he's called the Undefeated of the East.
 * From the same game we also have Don Zauser, a nightmare of a boss with massively higher armour, health, hit, and evade rates than any boss prior. Oh yes, he also has the highest level Prevail and recovers 1/10th of that health each turn.
 * This is brought up to eleven in the PSP port, SRW A Portable, which for various reasons may already be the hardest modern SRW game already. Master Asia is significantly easier if only because the new weapons upgrade system means your strongest attacks (probably Shining Finger Sword) are going to be as heavily upgraded as your anti-grunt weapons (Rocket Punch and the like) and you need to upgrade your weapons to retain your sanity anyway. Don Zauser, on the other hand, will make you want to punch a baby.

To elaborate, your team has been split into two at this point, depriving you of some of your best and most damaging units and pilots such as Amuro and the Mazingers (meaning no Final Dynamic Special) and by the time you reach Don Zauser, you would have fought through no less than two sub-bosses, a horde of mass produced Daitarn 3 each with 25500 HP, and you would have beaten down Cross, who not only has some 120,000 HP with HP Regen (S), but also manages to pack Prevail Lvl. 8 along with a Haro, which 90% of the time would signal the end of the stage.

Only then does Don Zauser show his face, and he has an arsenal of mech-wrecking moves, insane Hit/Dodge rate, stupidly-long range, and the "Prevail" skill. Combine this with his HP regen and insane HP count, and you'll find yourself discovering that the last 1/5th of his hp is much more difficult to take down than the other 4/5ths, which is less damage that what he'll be recovering. What makes it worse is that his unit size is LL, meaning a 20% bonus to his attack and defense since most of your heavy-hitter super robots are not available. At least with Dark Brain, the game gives you your whole army to smack him down.
 * Although people often consider handheld titles (especially those on GBA/NDS) are lots easier than console ones, there are still some painful spikes that can hurt. For example, Gauron from Super Robot Wars W. You fight him 3 times, and the former two are some real tough nuts to crack. To eleborate, his mecha (be it Codarl or Venom) has some really nasty long-range attacks (along with his combo ability), a barrier that reduce damage and an equviant of After Image (after 130 Will), all above become worse as he'll fire up to max Will (170) each time you face him except the last time, and for the worst HE USES SEISHINS: Concentrate (buff 30% hit and dodge rate) and Awaken (move one more time each turn), ON EVERY TURN. Oh, and he has Prevail too. Quite a chunk of players of W consider this sadistic bastard is EVEN STRONGER THAN THE FINAL BOSS, given by the situations. Below are the breakdowns of the first two, hard encounters:
 * On stage 9 (Earth route), you have your originals, the GGG crew, the FMP trio and some Endless Waltz casts. That's not too bad, considering the fact the GGG crew members are considered as "the Game Breaker team"... Oh wait. Since it's only stage 9 their SP amount is limited (as well as their limited amount of upgrades), so you won't be using Sure Hit all times. And the key to defeat Gauron, Mic Sounders (who has a weapon to reduce an enemy's mobility by 50%), probably spent most of his SP to survive the onslaught earlier before your cavalry arrive. And the main battlefield is in a base, so if Gauron moves onto a tile of base structures (either normal movement or scenerio ones), this will effectively gives him HP AND EN REGEN, as well as BUFFS IN DEFENCE AND DODGING. If you're playing normally, you don't have ANY ways to reduce his Will either. And after that, you still have to deal with Wufei (in his Altron, no less) and Trowa along with their goons, while you can't let Kurz's M9, Heero's Wing Zero Custom or Sousuke got blown up. There's always a reason for new players to choose the Space route rather than this.
 * The second time you face him will be Stage 35. Team wise, you're in a much better shape than before (you now have the GGG crew and a new bunch of Tekkamen at disposal), and your men must have lots of Sure Hit right now. But you have to fight a bunch of Elite Mooks first before going to deal with Gauron. And thinking to take him out ASAP this time? Hurt him once and he'll heal himself to full, AND USE HOT BLOOD AND SURE HIT IMMEDIATELY. If your units are sticking together (especially Sousuke or Mao, who must not be destroyed), you're going to get hurt, BADLY. And you have to immediately deal with the Radam invaders; several of them have MAP weapons that can hit multiple units. As a sidenote, the third encounter in the next stage with him is lots more easier since he won't spam Senshins anymore.
 * You thought Gauron was an ass in W? He is just as difficult in J aside from the Seishins. All his stats are around 200 and his Lambda Driver reduces the damage. The only units that are most likely to hit without Seishins are Yuu and Hime spamming the Chakra Extension. Venom does not regain HP and there are no HP and EN restoration panels either. So compared to W he is slightly easier.
 * The Super Robot Wars That One Boss squad welcomes its newest member, The Edel Bernal on Rand's route. First of all, he completely breaks the game's difficulty curve, which mostly varied between average to somewhat hard to sometimes easy with use of Game Breakers such as the Nirvash paired with Haman Karn or Amuro and their Move-Again spam. The Edel Bernal is much, much, much harder than anything before him, even the Overdevil. He has the highest HP in the game (250000 to 300000 depending on your difficulty in a game which doesn't let you do more than 30,000 AT BEST USING A SUPER-ATTACK WITH ALL BUFFS), has HP REGEN, the usual assortment of overpowered MAP and ALL attacks and skills. He also has additional +2 Will increases when being hit: damage him 3 times, and he's able to use one of his MAP attacks (at 110 will, another at 130). And he can moves TWICE per turn. In Hard difficulty he has a total of FIVE shots of MAP attacks, and the more powerful one now only requires 120 will. And to top it all off, you fight THREE of him-- the psycho was Genre Savvy to summon up two Alternate Universe versions of himself (in his own words, "since you're all coming at me together, I'll call up some buddies myself!"). But it doesn't end there: you must kill all three copies ON THE SAME TURN or they'll regenerate to full HP. The icing on the cake is that the final stage which you fight him is a very, very long, 3-part map which started with a tough boss fight and was followed by a barrage of mooks and has NO INTERMISSION, so woe befall the poor player who used one of their consumable items or wanted to rearrange their squad formations. Since you can only make one mid-battle save per memory card, the stage can become Unwinnable VERY easily if you slip up even once. Now imagine doing this stage on EX Hard mode, which bans ALL upgrades...
 * Setsuko's version of this fight is almost laughably easy compared to this monstrosity, since you only get one of him to beat even if it's a souped-up version. And he only has A-Rank in terrain adaptation, meaning those with S-Rank will be a lot safer.

Fire Emblem

 * If you are trying to keep every character alive while playing a Fire Emblem game, good luck if you're up against a magic-using boss with an extremely long range spell such as Bolting. Sure, it only has five uses, but that's enough to get your characters' HP low enough so the boss's underlings can pick him or her off before you get the chance to have him or her heal. This is notably annoying during one chapter of Ephraim's story in The Sacred Stones, if only because the chapter consists of moving your units in a spiral-type formation until you reach the boss. Just be thankful that the bosses don't usually move.
 * Chapter 7 of Genealogy of the Holy War does one better: the boss guarding the first castle has unlimited uses for his long-ranged Fenrir spell, and it's strong enough to easily OHKO many characters at this point in the game. The castle's on top of a mountain, and with no flying units available, your only option is to scale the winding path up the mountain while letting him take several free shots at you. At least that boss only gets his Fenrir Spell after like 11 turns, giving plenty of time for Shannan and his Balmunk, who starts very near from the castle, to hack him and his minions in small pieces. If you don't have the Balmunk, though, you're most likely screwed.
 * Additionally, there is a certain Dragon Master wielding a certain Infinity Plus One Lance that is guaranteed to make any player burst into tears. If the Elite Mooks with Sleep Swords, Slim Lances, and hyper-accuracy due to the Dragon Master's 5-star leadership aura didn't make you rage, the boss himself will. Nihil and good defenses makes him resistant, if not immune, to most tried-and-true killing strategies, and the sadistic combination of Pursuit, Continue, and insane speed means he'll either double your units normally, or double consecutively before you can counter. The only units that will stand a chance against this boss without being ludicrously gibbed are either your legendary-wielding bow-user, or your legendary-wielding sage. Oh, and if you're unfortunate enough to reduce his HP below 10 without killing him? For one turn, he'll dodge everything, and during his phase he'll fly and stab an unfortunate unit in the face. GLARGH.
 * On the subject of Long-range Tomes: FE 4's Final Boss, Yurius, has Meteor, and like all weapons in FE 4, it's unlimited use for enemies-- and he's all to happy to spam it when you're fighting Ishtar or the Dark Warlords. He'll also Charge you with it-- so "Reduces SPD to 0" means nothing-- he can possibly keep pounding a unit with it 'till that unit is dead. Oh, and he also counts if you dared to let his twin sister, Yuria die (or killed her): His main weapon, a Infinity Plus One Tome, HALVES you combat stats before anything even occurs-- then he's got a good deal of Attack power, regenerates 20 HP every turn... and when he's below 40 HP? Vantage/Wrath kicks in-- he goes first and criticals any non Nihil Unit, severely limiting your attack options. (Of course, if you do have Yuria, he's an Anticlimax Boss, cause she gets an Infinity Plus 20 Tome that nullifies his weapon's ability, and has enough RES to make his attacks do about 5 Damage... She regenerates 10 HP every turn.)
 * In one of the later games of the series, Path of Radiance, the Black Knight is a full-on Luck-Based Mission. Even if Ike has maxed Strength, Skill, and Defense, you still rely entirely on him activating Aether enough times to bypass the Black Knight's defense and self-healing. Leveling up Mist, the only healer you'll have access to in the fight, helps, but not that much. Oh, and you have five turns to win. (Fortunately, you're not forced to win to proceed, though you recruit a crappier unit if you don't win.)
 * Ashnard's just as bad, if not worse. On Normal mode he's not too bad, though only Ragnell, your dragon, and the laguz you've called for reinforcement can hurt him, despite the fact that there are a load of things that should be able to do the job (like a theoretical weakness to bows and wind magic--it even flashes as if it'll be double damage, but it does nothing due to his "blessed armor"). He is merciless on Hard mode, where he actually moves and goes after your characters, and you won't get the laguz reinforcement as normal. And once you strike him down? He revives, with jacked-up stats to boot! Like the aforementioned Black Knight battle, it's pretty much all up to Ike's Aether skill.
 * Blazing Sword, Lloyd's version of "Four-Fanged Offense" in Hector mode. Not only does he move, his stats likely outclass any of your units and he has huge avoid. What's more, this is a Fog mission and if you are not aware that he is in a different spot from Eliwood mode, and that he moves this time, you're prolly going to lose someone. To top it all off, he has a Light Brand, which is a Sword that deals magic damage and can do ranged attacks. "General attacking me? I'll just blast it with magic! Is that a mage coming to counter me? I will just get up close and butcher it!".
 * Speaking of Blazing Sword, the Boss Rush in the Final Chapter. Eight bosses, all with nearly maxed stats and the most powerful weapons in the game, released one by one, and they will all seek you out instead of staying put. But the worst are
 * If the Random Number God decides that Bauker ought to dodge every attack you throw at him, (as seen here), he can become That One Boss.
 * Blazing Sword has Zoldam on the Pirate Ship level (Chapter 17). All you have to do is survive 11 turns to win, but if you want to get an S Ranking in strategy, you have to actually beat him in seven turns. Easier said than done, as you're fighting a high-level Shaman with the overpowered Luna tome at his disposal, and you have to zergrush him in order to even get past the army of reinforcements. As if fighting him normally weren't bad enough, try doing it in seven turns on Hector Hard Mode (for added pain, you'll have to do it with mostly broken weapons and no money, which is extremely likely to happen in a typical S-ranked HHM run). Even without the logistics problems, killing Zoldam is likely the most difficult challenge in the game. It may well be That One Chapter for the speedrunner.
 * Shadow Dragon has two examples on Merciless mode: Gomer (Chapter 2) and Hyman (Chapter 3). Both wield Hand Axes, have ridiculous Attack, and doubly ridiculous Fight Speed for the point you fight them at. There are few characters when you fight them who can even survive ONE round because of the ridiculous Attack Speed, and with their absurd HP, swarming is out of the question. Hyman is That One Boss on EVERY difficulty level too, because his Attack Speed isn't even much lower on the lowest difficulty.
 * The Final Boss of Radiant Dawn is a doozy. Unlike any other Fire Emblem final boss, you have to destroy the eight barriers surrounding it. Each barrier has 90 HP, high evade, can only be damaged by certain weapons, and will send half of any damage it takes back to you unless you use the Nihil skill (there are only four of these) or the Parity skill (there are only two of these, and they have the side effect of neutralizing your support bonuses). In addition, it recovers 40 HP each turn, and the constant reinforcements will heal it even further. Repeat this eight times. Meanwhile, the boss itself cycles between an area attack that targets Defense, a 1-3 square range single attack that targets Res, another area attack that targets Res, another single attack that targets Def, and yet another area attack that silences everyone. All three area attacks hit everyone and can kill most weakened units very easily. The boss has 35 Def, so only the strongest physical units can deal decent damage, and to make matters worse, 50 Res, meaning your mages are dealing single-digit damage. Finally, if the boss isn't defeated by a certain overpowered mercenary leader, it will only get back up, recovering all 120 of its HP. The way that it just overwhelms you is completely unlike any other boss in Fire Emblem history... at least, in the US releases.
 * Wait, it gets worse: if you don't kill this boss in nine turns, it inflicts Stun on everyone, leaving your party powerless for several turns and able to be picked off by their mooks.
 * Zephiel from Sword of Seals. Murdock's not exactly easy, either, but that level is frustrating more for the large waves of reinforcements every turn than the boss.
 * The first few chapters in Sword of Seals are somewhat similar. While they don't have infinite reinforcements, it's not fun to take on a General with your low-level bunch 8 chapters into the game, and right after that is a Hero, laughing at your pathetic attempts to hit as he saunters left and right from whatever you throw at him. Now go try it on Hard Mode. Factor in the game's CPU-aligned Random Number Generator...
 * In general, Seals is extraordinarily cruel about weapon accuracy, which is a large part of the frustration. Some axes have a base hit of 50% or worse. The throne that every boss sits on also provides an Avoid boost of 30%.
 * When it comes to ridiculous Fire Emblem bosses, Ishtar of Genealogy of the Holy War might as well take the cake. Not merely content with being That One Boss, she insists on being a Recurring Boss as well! Not only are her stats absurdly high in each appearance, but she always wields the Tor Hammer tome, which has an insane 30 might, +20 skill, and +10 speed. Combined with her maxed out magic and speed stats, Ishtar is able to 1-shot most of your characters with perfect accuracy at 1-2 range. Unlike other bosses sporting legendary weapons, Ishtar has free range of movement every time she appears. Her first appearance is in chapter 8, before most of your units are even promoted; good luck landing a critical hit with Faval's Ichival, or you'll be losing some characters. For her second appearance in chapter 10, she's backed up by Julius (who's nearly impossible to kill at this stage of the game), and she won't leave until one of your units is dead. She returns one last time on the final chapter, flanked by three other difficult bosses at the same time. Better hope you have the Holsety tome ready by then!
 * is arguably even worse. He has an absolutely ludicrous attack power of 70, meaning that he will one-shot a lot of your units. To add insult to injury, his Fala Flame tome grants him ridiculous defence boosts, and his defences were high to begin with. You'll need holy weapons if you want to give him anything worse than a scratch. Oh, the Fala Flame also grants him high speed boosts, which makes his evasion skyrocket as well. If you don't have units with legendary weapons, high resistance, enough strength to actually dent him, and a shitload of healers... godspeed, soldier.
 * Radiant Dawn also gives us . With 100 HP and 50 Defense, plus healing a large amount of HP every turn AND negating class-mastery skills. The only things that do any considerable damage to him are the Wyrmslayer or Rexbolt. The latter can only be used by one unit (Ilyana), who he's pretty much guaranteed to splatter into a fine pulp if you try it. The next boss is much easier, since you can make him teleport into the middle of your strongest units unarmed.   is also surrounded on all sides by a metric crapton of the hardest hitting, most resistant Mooks in the game, and reinforcements come in every turn for something like a dozen turns before they mercifully stop. He also has an area of effect physical attack that does more damage the closer you are to him, which can easily kill units with low defense if you get too close. His stats, as said before, are ridiculous. And lastly, to top it all off: His mastery skill,   If that thing activates, you're DONE. Triple damage based from his crazy strength stat + weapon might? We're talking about something that only one unit you can get (who has, as maximum stats you will likely never ever see, 46 defense and 90 HP) could possibly survive, and if he does, he does it with 3 HP. And you get said unit after this chapter. Basically: If you don't have Nihil on them? Keep them really far away from the boss. It says many things about this guy when many people think he's harder than the already complicated Final Boss. And the funny things is, this is acknowledged in-universe.
 * 's got a glaring weakness, however: he WILL NEITHER ATTACK NOR COUNTERATTACK against . Even then, you need to supply them with additional offensive support, since the "recovering large amounts of HP per turn" means large amounts of HP. Think 30, when the two mentioned units are dealing 5 damage total.
 * From Fire Emblem the Sacred Stones, we have Caellach. Appearing in a long and painful That One Level as it is, he has a ridiculous stat advantage over the overwhelming majority of your characters; he is able to one-shot half of them with his Tomahawk, forcing you to pick away at him with your best fighters in hopes of causing Death of a Thousand Cuts, while praying to the Random Number God that he doesn't get a critical hit. And speaking of critical hits, he's equipped with an accessory that reduces your critical rate to a flat 0%, which is downright painful for fans of since for that character It's Personal, yet this character relies heavily on critical hits to do damage.
 * There's also Valter from the same chapter. His stats aren't absurdly high, but his speed is good enough to prevent doubling from many units. Thanks to his killer lance, he has a dangerously high chance of landing a critical hit, which will be more than enough to take out most of your units. To make matters worse, he also has the skill pierce, which negates defense and is also enough to one-shot a good number of your units. And god have mercy on your soul if Valter activates pierce WHEN he gets a critical hit; the resulting damage will instantly kill whatever unit is unfortunate enough to get hit. Oh, and he also totes a Fili shield, which negates the effectiveness of bows.
 * And to pour salt on the wounds, you have to fight both Caellach AND Valter in ONE CHAPTER. You can, however, steal their stuff with with Rennac (whom you picked up last chapter), or Colm (yet he may be a liability if you have not trained him much), but that's rather risky.
 * in Prologue 8 of New Mystery of the Emblem. She uses Elfire in a game where anyone who isn't a mage has little to no Resistance. As a result, her attacks do MASSIVE damage to all but maybe 2 people on your team. And since it isn't a Seize map, she can and WILL actively seek out your units. Squishy Wizard though she is, it's a difficult fight if you aren't expecting it and it can be hard to get up to her without someone dying, anyway.
 * This fight can also slam the brakes on any Lunatic playthrough, due to her 13 Magic on that level. Go back and look at the chapter number, and you'll see why that's such a big deal.
 * Earlier on, there's either of the Prologue 4 bosses, Athena and Jeorge. Athena is faster than almost your entire army (except for My Unit and Caeda), so you'll be seeing many double hits from her. Meaning that whoever fights her will end up dead or severely wounded. Jeorge is a Sniper. A SNIPER. In the PROLOGUE. In other words, he's Athena, but stronger. Though he can't counterattack at close range, he's able to move around, making that a moot point unless he's surrounded on all sides.

Other Games

 * Madagascar in Pandemic is notorious for closing its only port with the slightest indication of a disease, even if said disease is non-lethal and has no noticeable symptoms. Because the seaport is the only way into Madagascar, many Pandemic games have ended with the world void of human life everywhere but Madagascar.
 * "President Madagascar, a man in Brazil is coughing!" "SHUT. DOWN. EVERYTHING."
 * A little known thing about Madagascar is that it actually has an airport that's not visible on the map, which sometimes stays active after they close the seaport. However, given their reputation of going isolationist when someone in Akron, Ohio sneezes, this only makes them slightly less annoying.
 * X-COM's Chrysalids weren't technically bosses, but the missions that include them as enemies almost all count as a That One Boss situation. Especially Snakemen terror missions. Chryssalids have 110 action points, which is usually more than double the action points your soldiers have. they have enormously high Energy and above-average stats all around, especially Strength 110 (when your soldiers will be lucky to have 40). They are all heavily armored and with enough health to shrug off gunfire and, if lucky enough, missiles to the face. They have an incredibly fast melee attack. And every soldier killed by a Chrysalid becomes a zombie, WHICH WHEN KILLED BECOMES ANOTHER CHRYSALID. So most engagements with Chrysalids are either "spot a Chrysalid a hundred meters away, see it run up to you in a single turn, see it bite the heads off two or three of your dudes in the same turn and they all turn into hostile zombies which even if killed will then turn into more Chrysalids", or "suddenly hear the noise a soldier makes when he's killed by a Chryalid, and notice one of them managed to sneak up from behind your squad and kill everyone". What's most irritating is that they show up relatively early but are on par with the 2 other nastiest aliens in the game, and the missions they show up on you have to take or pretty much lose the game. Some very succesful players, once they learn that Chryssalid enemies are present on the map, often prefer to just level everything with missiles, grenades and high explosives while ignoring civilian casualties, rather than hunting down the little abominations one by one. Some players go as far as carrying primed grenades in their packs if Chryssalids are lurking about.
 * The final two missions of Para World pit you against the full might of the evil SEAS society. You have dinosaurs, spears, swords, axes, bows, and catapults. They have cyborg dinosaurs, robots, flamethrowers, and guns. Oh, and there's also the towers that do 100 damage a hit, which is roughly every second. However, the example that most perfectly illustrates how overpowered they are is a robot that is a high-level special unit for you-but a LOW-LEVEL unit for the SEAS.
 * Shining Force has the Marionette, at the Circus in Rindo. It has 35 HP (at a point where your characters probably have around 15-20), a spell that can kill pretty much any of your characters in one shot (and, if you're not careful with how you arrange your characters, more than one in one turn) with more than enough MP to kill off your party, a high defense, and it automatically regains about a quarter of its max HP every round. If you don't know what you're doing, it will defeat you easily. Even if you do, be prepared to revive a lot of characters after the battle.
 * And if you thought that was bad, wait until you meet Mishaela. Take the Marionette, up its stats to match the party's growth in the interim, and replace the Freeze spell with a Bolt spell that has an even larger area of effect and still does enough damage to kill all but the highest-HP characters. Oh, and also up the difficulty and number of the minions from "noticeable but not a big deal unless you're under-leveled" to "holy crap, that hurt!"
 * Phantasy Star Online Episode III: C.A.R.D. Revolution has Those Four Bosses:
 * The Leukon Knight, fought halfway through both the Hunters' and Arkz' stories, alternates between immunity to physical attacks and immunity to techniques at the end of his turn, so you're at a disadvantage if you've got a deck with no techniques. His AP and TP switch every turn as well, meaning that he can do lots of damage even without Action Cards. To top it all off, he can play special cards that instantly destroy your Items/Creatures or mess up their attributes.
 * And It Gets Worse. The Hunters' final boss, Pollux has an AP score that increases every turn, meaning the longer the battle takes place, the more damage she does. She will also shrug off any attacks that give less that 4 damage, so you'd better bring your big guns and pray she doesn't use her Defense cards. But Wait! There's More!! After the eighth turn, she gains the Pierce ability, meaning that she doesn't have to destroy your Items in order to give you the full brunt of her steadily increasing AP!
 * The Arkz don't get off easy either: they get Castor, who gives her opponents 1 damage every time she kills one of their Creatures (Arkz Story Characters don't take damage whenever their Creatures are killed except if they have the Unfilial attribute). And she doesn't spend any Attack Points to move, so she can get into attack range with ease. Not that she really needs to with her special cards that let her attack from the other side of the map. One of them multiplies the damage by 1.5 times a dice roll, just to twist the knife. The fact that she takes 1 damage every turn as long as she's above 10 HP is cold comfort in the face of all that.
 * And last, but certainly not least, is Amplum Umbra, AKA The Germ. The true final boss of the game, it is exempt from the eight-point limit of summoned Creatures, so you can have up to four powerful six-to-seven point monsters breathing down your neck. It also has the Rampage ability, meaning that if you're a Hunter, it'll do 4 damage to all your items, and broken Items mean one less HP keeping you from losing. If you're lucky, it'll use Meteor, which reduces both your Items/Creatures and its Creatures to 1 HP so you can easily kill its monsters. But don't let your guard down; for if it has 5 or less HP at the beginning of its turn, it gets half its HP restored, negating the progress you made in beating it. And the cherry on top? If you lose to Amplum Umbra, you have to start over from Castor or Pollux.
 * In the Expansion Pack of Starcraft, a lot of people find the eigth Terran Mission to be rather difficult, especially with the Torrasque respawning only two minutes after it dies, making it a potentially base-destroying unit the first time it is deployed then a major nuisance after that. But the eighth Zerg mission in the expansion is an absolute brick wall. Both levels require swift action and good co-ordination by the player against enemies with the entire tech tree at their disposal and superhuman skill with some units' special abilities. If you don't know the correct path to take, Terran mission 8 is nigh impossible. Zerg 8, with its crazy combined arms shenanigans, is far and away more difficult. (Zerg 10, "Omega", is arguably easier if you're good at defense, since at least you only have to kill one base at a time.)
 * Blizzard's real worst moment has to be The Frozen Throne's Night Elf campaign mission 7, the mission to Dalaran. Multiple hostile bases to contend with, four mission targets that can only be harmed by magic damage (which only a handful of units deal), and half an hour to do it (far shorter than it seems, with as much setup as the your army needs). Night Elf mission 8 is trivial in comparison.
 * Many, many, many of the bosses in Pikmin and Pikmin 2 qualify, especially if you're trying to keep all your Pikmin alive. Here are the worst offenders:
 * The Segmented Crawster, a Bullfight Boss that is capable of killing almost all your Pikmin very, very quickly. If you can manage to avoid its rolling attack, the rocks will probably do you in. The best strategy for this boss seems to be: "Bring all your red and purple Pikmin, use a Spicy Spray, and pray to God you kill it in one go."
 * The second (and third) encounters with the Queen Bulblax-- if her "squish 'em all" attack from the first fight wasn't bad enough, now she endlessly spawns a stream of tiny enemies out of her ass that, while extremely fragile, can devour Pikmin instantaneously.
 * The Titan Dweevil.  Oh, so you
 * In the first game, Emperor Bulblax. Giant, capable of eating many Pikmin with one swipe of his tongue, and with his only weak point being his face, which he can reach with his tongue, the Emperor is just brutal. He has tons of health that must all be taken in one day or else he'll get it back. The easiest way to damage him is to throw Bomb-Rocks in his mouth, which will probably result in your rock throwers being eaten. To top it all off, he starts jumping around the arena when his health is low. Anything caught in that will be dead in a second. And he holds the last part you need to get the good ending.
 * That blasted Fungus Humongous boss. If you don't what you're doing and attack it head on, he'll spray spores everywhere and turn your Pikmin into hostile fungal abominations. Cue Curb Stomp Battle from your previous allies and only ways to defend yourself.
 * One of the toughest bosses in the second game would probably be Man-at-Legs. It's similar to its relative, Beady Long Legs, the good news is, it can't squash your Pikmin by stomping on them. The bad news is... it has a build-in, laser-guided machine gun. Losing quite a few Pikmin is pretty much guaranteed. Insultingly, the treasure the first one drops isn't even anything useful. It's just . However, this first fight is nothing compared to the floor in one of the last caves where you have to fight it in the middle of a pool of water with very limited cover for you and your Pikmin to take.
 * In Operation Darkness,  of all people is that one boss. He has MULTIPLE high level flunkies with him, a heal spell that he uses QUITE often that heals 50% of HP, a powerful area spell, a spell that pretty much wastes a character in one shot, he gets SEVERAL turns to your one, and just to top it all off   As if you didn't have enough of a reason to take glee in launching a bazooka shell into his face!
 * While Jagged Alliance 2 normally is pretty manageable throughout, the fan-made mod, v1.13 includes the Drassen Counterattack. This is a wave of 40+ soldiers, with maybe 10 or 20 elites among them, swarming at Drassen the second you take control of it. Keep in mind that at most you'll probably have 2-3 mercenaries protecting each sector of the town since they don't always attack the same sector, and you have barely enough time to train 1 squad of regular militia per pair of Teacher mercs you have. It's easily the toughest section in the game, the reward being that if you set the enemies to drop all items, it will most likely give you an excellent boost in terms of equipment. Technically editing the INI file with the included editor can stop the counterattack from happening, but it's included as a default ON and there's no way in-game to stop it.
 * There is a way to prevent it if you're willing to be inconvenienced by long travel times. Take only the north and south thirds of Drassen, aka the north square (sector) which has the airport (absolutely critical) and the south sector which has the mine (critical as your main source of income in the beginning, less so later on if you can capture other mines); the attack only occurs if you hold all three sectors. Unfortunately, to leave Drassen in this state means that any movement between the two sectors will take in-game hours, instead of ten minutes in-game.
 * The Strategy RPG Yggdra Union features Gulcasa, the aptly named Emperor of Carnage. He combines ludicrous stats from the point in the game that you first meet him with a special ability that not only makes him even MORE powerful but prevents you from casting you own special abilities as well. Expect him to tear through your entire army Union like it was made out of wet tissue. The only way to give yourself a fighting chance is to inflict a Curse on him, which lowers his stats.
 * Any CPU hunter unit in Nectaris upon reaching 4-stars or more, as the CPU is much less likely than a human player to try and win a battle it's outmatched in, and will retreat everyone experienced back to a factory (but doesn't care about generic inexperienced grunts to its disadvantage.) At that point, surrounding them for the support-fire damage bonus is the only way to take them out. They're bombers who are as sturdy as your average main battle tank and on top of that have anti-air missiles as a secondary weapon. A maxed out hunter is quite fearsome indeed. Luckily, on some levels, the factory where they're stored is "unclaimed" and, with a few sacrificial lambs to hold back enemy soldiers, within your reach. Fortunately for you, the other uber unit in the 'basic' game, the HMB-2 Giant, is very slow and is best used in tandem with a Pelican transport. The CPU prefers to take the scenic route. By the time the Giant reaches your forces, the rest of his are already a smoldering heap. You can even defeat it with a single artillery piece, as it only moves two spaces at a time and the CPU constantly guides it towards you instead of zagging and cutting off your way around it.
 * The Command and Conquer games have missions in each game that serve as That One Boss.
 * Two GDI Command and Conquer 3 missions are surprisingly difficult. The Alexandria mission is a fairly standard mission that just happens to be extremely difficult (even though it was featured in the demo), but the Croatia mission (just 2 missions later) is made of Nightmare Fuel. The first phase of the mission has you defending a crippled GDI base that has no construction yard, entrance points on the North, South, East, and West sides, and only enough power to have the defenses turned on for two sides at a time. Meanwhile, you guessed it: Nod sends waves of attackers from all four directions. You have to defend this base for 10 minutes. Then a convoy arrives, including a construction vehicle, across the river, but Nod forces have turrets and several garrisoned buildings over there. And they send suicide bombers at the construction vehicle. You need to (slowly) drive past and/or destroy the Nod forces while protecting the construction vehicle, while STILL defending your base, which isn't any easier than it was before and still requires plenty of micromanagement. Once you do manage to get your construction vehicle across the bridge and into your base, you can finally start building stuff again, but it's still a good 10 minutes before you're able to have anything resembling a stable base and build up enough troops to finally start killing the Nod bases that are sending troops at you.
 * Possibly THE hardest mission in the game is the last Nod mission or Hard level. The goal is to protect the alien tower Threshold 19 from GDI attack. The problem? GDI shows the player just what exactly tank rush means with Predators advancing in the dozens with half as much Mammoths as support. Although they aren't attacking the player, the tower is protected by a Scrin base who are on the receiving end of a Curb Stomp Battle: if GDI destroys the phase generators they're guarding, it's mission failed. These very phase generators also happen to be under attack from a band of Juggernauts as soon as the mission starts. Building up a decent-sized vehicle force to fend off the attack on the generators is impossible in the meager time available, and Zerg Rush of Venoms also impossible to pull off since the dozens of APCs, Pitbulls and Mammoths just swat them out of the sky like flies and building more is not an option even if four harvesters are working on funds, there's just not enough money and time.

On Medium, it is possible to drive a wedge between the two armies via an Outpost surrounded by Obelisks to give the aliens enough breathing room to build up and eventually counterattack (they even build a Rift Generator and deploy it against GDI repeatedly if you let them, Kane bless 'em); nuking the lower GDI base also lifts the siege of the player's base and removes all GDI infantry from the fight. On Hard, by the time the nuke is ready to launch, GDI has already blown away two phase generators, with a mass of tanks advancing on the defenseless third. Oh, and just to get to the main battlefield, you have to make a big detour since your base is facing the opposite side of the Scrin base. As a little good news, the Scrin won't attack you if you stay out of the way so you can focus on finishing the mission by blowing GDI off the map.
 * Scrin mission 3 in Kane's Wrath is also pretty hard unless you manage to salvage some Juggernauts to remove the Sonic Emitters protecting the GDI base.
 * The last China mission in Generals. You have very very few resources to build up with, the GLA constantly attacks, and worst of all they start off with their superweapon, which they WILL use. Repeatedly. On parts of your base they shouldn't even know exist. The GLA army also has a Scud Storm that is scripted to fire if your funds go above 5000. That means you can't capture the oil derricks.
 * China 4 in Generals: Zero Hour requires pure luck to beat. Lots of it. A mission that demands speed due to a strict limit, the map is absolutely cluttered with invisible land mines capable of wiping out several tanks at once, meaning you go slow or die. The enemy makes extensive use of artillery in the form of rocket buggies and SCUD launchers, and is smart enough to run away when you send troops to attack said units: their artillery is faster than any of your own units, making it trivial for them to get away from you-- or lead you into some mines. It would be easy enough to handle if you had access to China's Helix helicopter or MiGs to provide some air support against said artillery, but they are not available in this mission. Ultimately it comes down to extensive use of the Artillery Barrage support power and praying that their rocket buggies and SCUD launchers make horrible pathfinding decisions.
 * Homeworld 2, mission 12, especially if you have a full fleet. The enemy sends you massive, massive fleet against your position, with something like at least 7 battlecruisers, and lots of other ships combined. Cheating is not an option either; increasing your fleet size also increases that of the enemy.
 * Valkyrie Profile Covenant of the Plume: despite being the Final Boss of A-Path, Gram easily qualifies. While the other late-game and final bosses are merely very hard fights, Gram simply does not fight fair. To even get to him you have to go through six Pale Flames. The Pale Flames are spellcasting enemies with three attacks per turn AND a Great Magic spell. Other enemy spellcasters only get one attack per turn, and only get Great Magic if they're bosses or end-game mooks. Once you engage Gram, you find out that the usual 4-on-1 tactic that dominates the rest of the game won't work-- his counterattack hits every attacker and will kill them all barring a lucky Survival activation. So attacking with your whole party at once means a Total Party Kill on the counterattack. And if you try to whittle him down slowly with 3-on-1 attacks while keeping a healer out of his attack range, you get a nasty surprise in the form of a Heal spell that restores him fully when he hits 50% health. While winnable, the fight can literally take 2 hours of carefully planned maneuvers-- longer if you're not lucky. By this standard, the B-Path Final Boss throwing out 40-hit combos twice per turn seems pretty reasonable.
 * The C-Path Final Boss,, can also be like this if you've sacrificed too many comrades, since   If you kept at least three strong allies, she's not overly difficult, but if you went crazy with the Destiny Plume,   (Honestly, though, if you sacrificed so many that you don't have a full party anymore, you have bigger problems.)
 * Nearly any mission with a rescue objective is a pain, but the absolute worst is the one at the end of Chapter 4, B-Path. It comes right after another battle with no save point in between, and the NPCs you have to keep alive are clear across the battlefield. Diagonally. Plus, while one of them puts up a hard fight, the other is a weak archer with feet nailed to the ground who will die in two turns if you don't get there in time. Without Dashes or Provokes (admittedly both very common skills) it is flat out impossible to win the battle. Even if you make it in time, you still have to deal with the enemies as usual, including a punishing Iron Golem. And your reward for success? The NPCs you were protecting die anyway.
 * The Europa Universalis series, which simulate Europe from (varying from game to game) the 1400s to 1820s, has two in the grand campaign. In the first two games, it's typically Austria which, thanks to scripted events that let it insta-inherit Hungary and Bohemia, will basically take over all of Europe unless you devote yourself to its destruction. In Europa Universalis III, it is most definitely France. France has a large economic base with a large population, which lets them support a huge army to start with. To make matters worse, they also pick National Ideas that make their armies superior. And as icing on the cake, the only country that has a chance at stopping them at the start, Castile, always plays buddy-buddy with them... even when France is busy taking over everything that ISN'T Castile in Spain. Very, VERY frustrating. Worst of all, if you can beat France, odds are this has given Austria the opening IT needs to take its title back.
 * Asian countries have to deal with the advanced (as in: Europe doesn't even get it for 50 or so years) starting government, ungodly manpower, full centralization and production revenue that is Ming Dynasty China. So do Indian countries, because nothing short of divine intervention can keep the Chinese from steamrolling through Central Asia and and all the way through to the Ottomans, who they usually beat. To make matters worse, weakening them significantly will allow Japan to become the dominant power, and Japan can declare war on any other country without stability hits and actually takes military national ideas.
 * Scenario 12 of Warsong (North American release of Langrisser 1) is the Two Towers, wherein you fight Emperor Python. It's a forced arrangement, your commanders are split into two groups, and you're up against powerful enemy units such a Lords, Archmages, and Grand Knights that will make mincemeat out of your characters if you have not levelled up properly and your commander is not able to hire the correct troops to counter theirs. It doesn't help that a lot of your weaker defensive commanders are surrounded by commanders with archer units. On top of that, two commanders, the Lord guarding the hall connecting the two towers and Python himself, get the extremely powerful Royal Soldier troop. Unless you've played through this scenario a couple of times, you'll be lucky to get out with more than just Garrett alive (once a commander dies, they're dead for the duration of the game), and if he's not on his 3rd class (both of which still have lower stats than Python), you'll either be starting the game over for the beginning or abusing cheat codes to replay earlier scenarios. Oddly enough, the scenarios that follow this once are considerably easier.
 * Heroes of Might and Magic V: In Tribes of the East, the final battle for the orcs. Not only are you forced use the weaker of the two heroes, the enemy uses the orcs Achilles Heel, dark magic. Even if Kujin has Shatter Dark, the constant flow of Frenzy spells will wreak havoc on Kujins rather unimpressive army, unless that same spell works in your favor (Frenzy simply makes the target attack a random nearby stack). Every other significant battle in the final mission, even the last one, pale in comparison.
 * The second orc mission can qualify as well, depending on your luck. Even though there are no siege battles and all orc towns on the map join you when you approach them, if you are unlucky, the AI will constantly assault your second town from a one-way portal with armies far outnumbering your weekly growth, rapidly thinning your troops and maybe even forcing you to garrison your main hero in that town.
 * Hide 'n' Seek Battle Monster Tactics has a potential one in Trinchula, the first Target Monster of B5. It is highly resistant to every element except . Since Kevin can have only one technique at all at the time, it is virtually required to have  on your battle team, which is made unpleasant by the fact that there are two  monsters just waiting to take down your only character with a constant chance of dealing decent damage to Trinchula. What's worse is that . Unfortunately, if you don't have the character sufficiently leveled up (elemental multiplier includes the enemy's defense in this game, which means it won't help much at all with insufficient attack) and on your team, have fun dealing single digit damage to this triple digit HP pain.
 * First time players of the Doujin game Battle Moon Wars will probably tear their hair out in frustration when they face off against Emiya Kirigitsu, Irisviel von Einzbern, Sella and Leysritt who are all besides each other in a row. Between them and your team are hordes of enemies, most of whom have a defense support (the bosses even get FOUR of it) which, unless you're not a perfectionist and do not want to get, makes things harder to kill. Oh, and you also get one Spoony Bard of an ally who cannot die under any circumstances or else it's Game Over. (Fortunately, you can just let him sit at the back with no problems, but he's still a waste of space.)
 * The Eldar Falcon Tank from Dawn of War 2. It has powerful and annoyingly precise guns that can kill your men in mere seconds from large distance and if you try to revive them, it will just kill them again without even moving! You have to lure the tank away with good chances that the bait will end up dead as well. The only one who can get near enough to use the anti-tank Melta bombs is the scout Cyrus, but if he's yet to learn an ability to throw the bombs without breaking stealth (and it's quite a high-level ability), he will be shot immediately after the throw (it takes more then one bomb, naturally) and then... see above. If he does get said ability though, the boss becomes a cakewalk... as well as almost every other one after him.
 * The fight against if your whole team remain pure. He has a custom Chaos Predator that is essentially a Space Marine Predator on steroids. The tank will wreck your party in seconds, even if they have Terminator Armor.
 * Sid Meier's Pirates! has a nasty one in Marquis de Moltalban. First of all, you have to hunt him all over the Carribbean, and he usually favors ports on the ass end of the map, like Vera Cruz or St. Augustine. You find him, and he is sailing a tricked out War Galleon with full crew and all upgrades. THEN, you have to fight him, and he remains wicked fast and skilled - age slows YOU down, but not the guy who was already white-haired when your character was but a lad. After having to fight him four times for the map to his hideout (which is usually in Nicaragua, far away from any ports to refuel or other plunder to keep your crew happy), you have to put you and your crew against his mercs in land combat. then, you have one more go at him before you take him down for good.
 * Blackbeard is a Combat Pragmatist-- or less diplomatically, a DIRTY ROTTEN CHEATER. He lights his namesake beard on fire before the battle, producing graphical effects that slow down the game and cause Interface Screw. For what it's worth, the real Blackbeard also did this, but for a different reason: to terrify his enemies by looking Like a Badass Out of Hell.
 * Selvaria Bles in Valkyria Chronicles definitely holds this trope. The first time you fight her, she can effortlessly slaughter your foot units; the only way to really stop her is to block her from your soldiers with your goddamn tank. The second time? She gets anti-tank capabilities. Did I mention that if the main character's tank is destroyed, it's game over?
 * You would think the mission where she faces you as a regular human instead of a Valkyria would be easier, right? Guess again. She gets a Gatling gun with a range that can hit anywhere on the battlefield she has a line of sight to, and she reloads in no time. Not to mention that she dodges every attack that isn't from behind, is sitting beyond FIVE BASES worth of defenses (and continuous reinforcements) and will make plentiful use of the Heal All order. Oh, and things like mortars and grenades, which are the usual way to deal with Aces and such that dodge attacks? She's TOTALLY IMMUNE TO THEM.
 * While technically not a boss, Ty the Immortal has an honorable mention. He must be blessed with ESP, as he will dodge every goddamn attack you throw at him, even if you're sniping at him from across the map. Ty also has the dubious honor of appearing in multiple missions, even if you killed him in a previous chapter.
 * EVERY Enemy Ace does that. None of them are bosses, or even required to kill, but you get amazing weapons if you do defeat them.
 * The Total War series had a few factions that could count. Medieval 1 had late game Turks/Ottomans. Left unchecked they will take over half the world map, they will have roughly 70 full stacks of troops, and will accept nothing less than your complete and utter destruction.
 * Medieval 2 has the Mongols. They can show up at one of three different spots on the map, at a random time, with more stacks than spread out your entire kingdom. All of them heading towards your capital. If you're not prepared for them by that point with some decent anti-cavalry, you may as well delete that save. Oh, and they were just a warm up. Yup, just like in real life, the Mongols are utter combat monsters.
 * Empire Earth has Grigor II. The thing itself isn't too bad, since a squadron of weak flying robots can pound its health away fairly quickly with it having no way to retaliate, however his SCENARIO is pure evil. A Bad Case of Deja Vu is easily the single most difficult scenario in the entirety of the game. To clarify, you have Modern Age technology, and command the near-worthless city of Voronezh you destroyed effortlessly in the first scenario, while Grigor has both Russian cities allied with him, with time vortexes warping in Nano Age technology constantly, nevermind the fact that Volgograd has completely functioning production buildings upgraded to max. What's worse? Your gate is nuked in the opening cutscene, that's what. Oh, and the vortexes themselves are at the very back: Volgograd has one too, so Grigor II has doubled unit production, and the only way to reasonably destroy one is to nuke it, which, considering the fact that AA tanks and AA guns are all over the place is quite flatly near impossible. The entire scenario can be summed up simply by saying that The Computer Is a Cheating Bastard, and that you're on the receiving end of the Curb Stomp Battle that was the first scenario. Oh, and 2.0 added Hard Mode. Good luck.
 * The little known game Rise of Legends has the Doge in the first campaign. He rides around in a Humongous clockwork contraption about twice as big as your heroes with at least half a dozen Doge Walkers to back him up. It doesn't matter what mission you're attempting, if he is in (or nearby) the province you're attacking (the game uses a risk style map) he and his army will destroy you. Better have three Ultra-Juggernauts in your starting army if you want to stand a chance at all. Luckily for plot reasons he wont' show up to defend his capital in the final battle so its possible to never fight him in the entire campaign.
 * Starcraft II has Maar, one of the few legitimate bosses in the game. Normally, you need to complete the mission objective to kill him for good, otherwise he revives after a while and slowly grows in strenght each time. The Immortals make short work of him though. On Brutal, he revives in seconds, and the main base is protected by a lot of air units while you only have Stalkers to deal with these.
 * Mentioning Midas in Record of Agarest War will make people scream in frustration as to how hard he really is. Even if you bought the Downloadable Content, he's still pretty hard. He could really qualify for a Wake Up Call Boss if it weren't for the fact that he's one of the bosses of the third generation, but this is the boss where you really need to think of strategy. Not only is his Phoenix Strike a One-Hit Kill, he can hit people at two squares apart, and he can regenerate 1/4 of his health per turn.
 * Eternal Poison has Ignis. First of all, getting him to appear in the first place is a right pain-- you have to capture one of each of the four types of Majin on the map. For those unfamiliar, capturing a Majin requires you, on its killing blow, to deal a set number of damage above what was needed to kill it. This Binds it, which leaves it immobile and ready for capture. Sounds easy enough, right? WRONG! Not when the Nightwalkers can snipe you from 5 spaces away with a third-level Malus spell. Or when the Armatuses can eliminate your fighters' ability to attack whatsoever by inflicting Fear. And especially not when the Acridas beat you down with their ludicrous physical attack strength whilst inflicting Sleep so it can destroy your fighters more. Hopefully you have a fighter who's good with Strike attacks, or else you're going to have a right old time with the Zyr Phantasms, who besides taking two people to capture in the first place, resist to varying degrees ALL MAGIC.

Once you've suffered through the above terror, Ignis graces you with his presence. Bosses in this game have these things called Demon Auras, which are specific requirements that have to be met before you can damage them-- for instance, Terranus, the boss who precedes Ignis, requires a combo attack to be performed on him before your fighters can all hurt him. Now, Ignis's Demon Aura is that you have to hit him with a Pierce, Strike, and Slash attack before he can be hurt. That's all well and good, but it's entirely possible-- and likely-- that the player is fighting Ignis as Ashley, who has no storyline characters who attack with Slash. The only hope in this case is to have a mercenary with Slash-- and that they don't die before they get to Ignis. Ignis has backup in the form of Pyromotes, which can snipe you with insanely powerful Pyro magic, and the Exo Machina, which can Fracture you, heavily decreasing your stats. And of course Ignis himself has bucketloads of Fire magic himself FOUR spells of it in total, including an area-of-effect spell. He's also only weak to Water and has a whopping 570 HP. And, of course, God help you if you want to capture him-- you're gonna need to do 180 extra damage on the killing blow, and have two people left alive to capture him with. And those Pyromotes and Heeflers with him? Pyromote can bring Bound Majin back with half HP, and as an AI priority Heeflers KILL Bound Majin, preventing you from capturing Ignis.
 * Ymir the Norse Titan from Age of Mythology: The Titans campaign. You have to stop the him from destroying the villages on his way to your base, but this is difficult because he can easily kill your soldiers and he sends enemies to attack your base many times throughout the mission, which makes it very annoying to split your army between stopping Ymir and defending your base. Folstag can stun him with his breath, but even so, Ymir makes the mission quite challenging.