Foe Yay/Dissidia Final Fantasy

Let's be honest. The Final Fantasy series always had a thing for making the protagonist's and antagonist's relationship feel... rather personal. Therefore, when you put together the ten main heroes and ten main antagonist of ten games... well, THIS happens! Awkwardness and creepiness ahoy!

And now, some of the more notorious examples are illustrated in this picture!

Squall
"Ultimecia: "Shall we dance?""
 * Ultimecia's "failed" Pre-Mortem One-Liner to Squall:

"Ultimecia: "So you would rather die hard.""
 * Let's not forget Ultimecia's response to Squall's breaking through her barrage in their pre-duel cutscene:

"Cloud of Darkness: "Gun me down, if you can.""
 * Not to mention Ulty blatantly stroking his face. Sure, she had just went all ZA WARUDO! on him and was attempting to deliver a deathblow right afterward, but the fact that such a gesture was the last thing she does before trying to off him...
 * And speaking of these two, it's probably unintentional but worth noting that the end-credits montage, which features the Heroes' cutscenes from Destiny Odyssey, has Squall and Ultimecia's scene set to a snippet of "Eyes On Me", their game's love theme.
 * Things get further unusual when Squall, the group's Team Mom, has to fight Warrior of Light, Team Dad in general. Look at it carefully and you might see a resemblance to a couple talking about how they should treat their children.
 * Even more apparent in 012, where Squall's intro to Bartz is "Would you stop fidgeting?" and sounds more like a mother preparing her kid for a flu shot than a combatant.
 * If you squint, Cloud of Darkness' Encounter quote for him. A challenge, or something more? Both, maybe?

"Lightning: "It's time for your lesson, schoolboy.""
 * Lightning's intro quote is very, interesting. This is especially the case with her rather assertive attitude and rather commanding voice.

The Emperor
"The Emperor: "Do you intend to pick my pocket?""
 * While not particularly obsessed with Firion, his lines to certain opponents can be... interesting.
 * Towards Zidane (it's mostly the tone, but the line itself isn't entirely innocent):

"The Emperor: [chuckles] "Why don't you let me control you?""
 * Towards Terra:

"The Emperor: "Ought you not be on our side?""
 * ... Why does that sound like Jareth?
 * It doesn't help that he seems to be eying Terra out in the Dissidia opening and in the CGI parts of the Duodecim trailers.
 * His line when facing Cecil lends itself to... interpretations, both tone and line alone:

"The Emperor: "Let us crown the true master.""
 * And check Kuja's entry.
 * Moreso Minion Shipping/Unholy Matrimony than pure Foe Yay, but most fans see something going on between Mateus and Ultimecia given the sheer number of scenes in which they are seen plotting together. His Encounter line towards her in the original Dissidia suggests something of a Worthy Opponent-like relationship. As one fan best put it, "it's merely a matter of who tops".

Cloud of Darkness
"Cloud of Darkness: "The truly mighty must be leashed.""
 * Cloud of Darkness has quite a lot of Foe Yay with everyone thanks to her husky voice, but special mention must go to her BDSM-licious response to Sephiroth:

"Tidus: "I can score even in the dark!""
 * After fighting Laguna, the former soldier gets, er... "Distracted by the Sexy her appearance, though not by any particular PART of her appearance", and then, after she discovers that a) Laguna doesn't see himself fit to be one of Cosmos' chosen, b) his protests that he's not taking orders from her, just helping her, and c) his desire to fight the manikins to help out his war buddies (an act that ), she takes a curious interest in Laguna's methodology and becomes his personal enemy for the rest of the 12th cycle, while assisting him in reaching his goal.
 * If you consider Squall's own example with the same lady, Foe Yay with her must apparently run in the family.
 * Tidus's encounter quote when he fights her:

Kefka
"Kefka: "Time to come home to papa!"
 * Kefka's obsession with Terra is also utterly creepy. Of course, given that he's a Monster Clown, that's the point, but still, check the lines:

Kefka: "Hello, my pretty!""

"Kefka: "Ooh... aren't you hot!""
 * And then there's Destiny Odyssey 42, and 'nuff said.
 * And while this line may be an somewhat incorrect translation, or just easy to misinterpret, Kefka's pre-battle one liner to Firion speaks a lot:

"Kefka:"
 * It's a bit of both. The line in Japanese roughly translates to "You must be sweltering", referring to the amount of gear Firion carries.
 * And don't even asks where it goes if you have Kefka fighting himself...
 * For the curious, it's:

"Kefka: "You better straighten up missy, or I'll hafta teach you a lesson!""
 * Dissidia 012 ramps up the Foe Yay between him and Terra to the point it rivals Cloud and Sephiroth. His comments about her sound like as an abusive parent at best and an abusive lover at worst. When she resists his control he tortures her into submission with the line "Sorry babe, I only hurt you because you make me!" When she escapes he remarks "she always comes running straight back into my arms," and he has pet names for her, including "sweetcakes" and "dame."
 * Then, less perverted but no less disturbing, is this gem.

Sephiroth
"Sephiroth: "Such a good boy! You've come back to me where you belong."
 * ALL of Sephiroth's dialogue directed at Cloud. ALL OF IT! And it only gets creepier as it progresses.

Sephiroth: "On your knees! I want you to beg for forgiveness.""

"Tifa: "You're not even gonna tell a girl your name before you stab her?!"
 * Heck, he has Foe Yay with everyone, to judge by the quote he uses after executing one of his attacks: "You look good."
 * And everyone certainly seems to make a big deal out of Sephiroth stealing Firion's rose, especially when you're told he's run off to the enemy's stronghold by himself because "something precious of his was stolen." (It doesn't help one bit that the guy's Japanese Fan Nickname translates to "virgin.")
 * 012 has Tifa Lockhart. However, her normal intro quote is anything but this trope. Her intro quote in one of the reports however....

Sephiroth: "You don't remember me. How very tragic.""

Kuja
"Ultimecia: "By now, Kuja should be having his way with Zidane and Bartz.""
 * And of course, the rather feminine-looking Kuja's obsession with Zidane also deserves mention. Not only does he have four encounter lines for him, but Ultimecia makes it all even creepier.

"Kuja: "You think you can dominate me?""
 * Yuck. That would be Sibling Incest.
 * And then -- more Ho Yay than Foe Yay, but still in a battle -- there's his encounter line for The Emperor:

Others
"Terra: "What do you intend to steal from me?""
 * Not that they're actually foes except in the sense that they can fight each other, but Terra will deliver this line to Chivalrous Pervert Zidane before a fight:

"Ultimecia: "I wonder if you can dance with me.""
 * While Zidane isn't interested in hitting on the one actual female on the Chaos side, she doesn't hesitate to deliver an interesting encounter line to him.

""Kneel before me if you seek comfort.""
 * There's even a bit of Foe Yay between Chaos and Cosmos. Well, apparently they were lovers.
 * Or mother and son. Not that the two are necessarily mutually exclusive.
 * Chaos's pre-battle taunt to Sephiroth is more than a bit suggestive, seems the latter's attitude towards Cloud is contagious.