Orcus on His Throne/Playing With

Basic Trope: The villain, despite his seemingly overwhelming power, spends most of the plot doing nothing and never directly interfering with the heroes. He only gets involved when the heroes finally storm his castle looking for his head.

Straight: Emperor Evulz is the Evil Overlord of the story. When he hears that heroes have arisen looking for his head, he sends his Mooks, Quirky Miniboss Squad and The Dragon out in sequence to deal with the pesky heroes, but never thinks of going out and busting their heads personally despite being powerful enough to destroy them with a gesture at that point.
Exaggerated: Emperor Evulz never does anything, plot-related or no, except sitting on his throne. He leaves The Dragon to do everything, including commanding his legions of terror and his evil empire.
Justified: Emperor Evulz is busy with the everyday running of The Empire; arranging firing squads, plotting invasions of The Alliance, directing his troops to defeat rebels, making sure slave-whipping quotas are kept up, arranging for the daily Puppy-Kickings, so on. He's got better things to do and leaving his lair to put down every upstart scrappy hero personally would be murder on The Empire's day-to-day efficiency.
- Evulz's power is explicitly tied to his evil lair/non-movable Artifact of Doom. He can't leave the presence of his power source, or he'll be no match for the heroes.
- Evulz's power is all smoke and mirrors. In reality, he can't fight his way out of a wet paper bag
- Evulz realizes that if he gets off his throne and starts kicking ass, the battles will soon just end in Curbstomp Battles, so he decides to sit and wait for them to come to him.
Inverted: The heroes never do anything heroic, except for serving as some sort of distant moral beacon for other rebellious elements in The Empire. Evulz is forced to go look for them, putting down a bunch of unrelated rebels in the process.
Subverted: After his initial Mooks fail, Evulz decides that these heroes should be dealt with personally.
Double Subverted: ...Only to stop half-way through, go back home and send The Dragon out instead.
Parodied: The reason Evulz never bothered to do anything evil personally is because his throne is so incredibly comfy. When The Hero and his companions finally storm his throne room, they must contend with an Evil Overlord who never bothers to leave his Comfy Throne, even through the boss fight.
Deconstructed: Evulz never leaving his evil lair, yet his evil continuing on, causes him to become Shrouded in Myth and an overhanging and looming threat whose sheer presence is more damaging than anything he could do directly. Everyone in the world ends up living in constant abject fear of this never-seen, mythic figure, unaware of whether or not Evulz even exists anymore or not.
- Alternatively, Evulz's severe lack of initiative causes his own forces - even his "loyal" generals - to turn against him and eventually dethrone him.
Reconstructed: The heroes soon convince everyone otherwise. Evulz turns out to be a real person, but generally uninterested in the world around him that explains why he's never seen.
- Alternatively, it turns out Evulz is a very skilled manipulator and that he even orchestrated his generals' betrayal so that he could weed out the disloyal factions of his forces and cement his power. It becomes a Xanatos Gambit when one considers the first deconstruction: If they're too scared of him to revolt than that works to his advantage too.
Zig Zagged: Evulz takes to the front lines at random intervals, to keep his enemies off balance.
Averted: Evulz arranges for a Final Boss Preview with the heroes.
Enforced: "We can't have the bad guy out doing things. He's far too powerful, and if he actually did anything to the heroes before they were ready, they'd never be able to beat him."
Lampshaded: "He never seems to do anything himself, does he?"
Invoked: Evulz acts this way to make people underestimate his personal power. Meanwhile, he sends out his less competent minions to make the heroes think he obeys the trope, only to laugh in their faces and obliterate them when they burst, underleveled and unprepared, into his evil lair where he keeps all his competent troops.
Defied: Evulz devotes his entire time to finding and rooting out anyone who might oppose him, no matter how trivial they might seem at first.
Discussed: "Go tell Evlulz to come out here and face us himself!" "Bah! Our master has better things to do than kill meddlers like you at every turn. Now, prepare to feel the wrath of his chosen Psycho Rangers!"
Conversed: Two characters, looking at a show containing a classic Hero's Journey, note how the seemingly overpowering Evil Overlord never seems to get off his bum and interfere directly at any point and always seems content with the Status Quo. Bonus points if the characters themselves are an Evil Overlord and The Dragon in a Villains Out Shopping moment.
Played For Laughs: Evulz is literally glued to his throne.
Played For Drama: Everyone sincerely hopes he stays in his throne room, because if he starts kicking about, Things are about to get seriously ugly.

You can click here to go back to Orcus on His Throne... Or you can choose not to. Frankly, this page is very nice and relaxing, and haven't you done enough troping for the day? Wouldn't you rather just sit here a few more minutes and take in the glow? Re-read a few of the examples perhaps?