Why Fuuma x Kakyou
Most people, if they have an "OTP" for Fuuma, pick Kamui, and if they have one for Kakyou, they pick Hokuto. I do not. I think neither of those relationships is what Fuuma or Kakyou needs, and in fact, both have led them to rather destructive extremes. There is a concept constant in CLAMP's manga, about how each person has one single most beloved person, someone for whom one will go to extremes and sacrifice anything. I honestly believe that this is what Fuuma and Kakyou are to each other, that there is no better match for Feither. In fact, I believe that they're each other's only hope for happyness, they could be each other's redemption and rebirth... if only they gave themselves a chance. If only they realized in time that they already ARE together and that they don't need to, and should not, hang on to ghosts from the past.
That's the great tragedy of it. As things are in X, it's unlikely that they'll realize it in time. And even if they do, they have to let go of the past, they have to let go of their respective obsessions. And X being what it is, their obsessions are DAMNED STRONG. Fuuma has chosen to deny himself almost completely because of Kamui, he has chosen to make most of his life (and his possibly death) revolve around a childhood friend that refuses to see him as he is; and Kakyou has given up on life because Hokuto is dead.
So taking that into account, how do I explain my belief that they should be with each other, that they WANT to be with each other?
When they first met, theirs was a arrangement of convenience. Kakyou would use his dreams to guide Fuuma as a Dragon of Earth, and in return, Fuuma would grant his wish, in other words, he'd kill Kakyou when the time came. In that first meeting, there is a lot of tension, and more than a fair bit of dominance and submission play, but you don't get the feeling that these two care about each other. How could they? They just met. However, their relationship changes over time. They spend more time together, they get to know each other. Fuuma is always every bit as possesive and dominant with Kakyou as he is in that first meeting, but he also comes to be incredibly tender towards the yumemi. That was probably what attracted me to the relationship from the start: it's one of the ways in which we see Fuuma's "other side". He's NOT sadistic or evil with Kakyou, in fact he's gentler, more tender and caring with Kakyou than he's been with any other character in X. He was never this loving with Kamui, back before fate made them enemies.
So why is Fuuma so tender to Kakyou? What makes him so special? Well, most people don't realize this (being blinded by Fuuma's supposed sadism), but Fuuma always was and still is a protector. It's BECAUSE he's a protector that he's ended up being the Dark Kamui. Fuuma's great tragedy is that to grant people's wishes, he often hurts them, and that fate and his own choices have turned him into the antithesis of te only thing he ever wanted, which is to protect his loved ones. Fuuma, as the Dark Kamui, doesn't have many people he can protect, in the most traditional sense of the word.
But he can protect Kakyou. In fact, if ever there was someone in need of protection, it's the frail, comatose Kakyou. Not only is he completely helpless PHYSICALLY, emotionally he's also extremely frail. And yet, he doesn't let most people see the extent of his sorrow. He certainly has never let Hinoto or Kamui see it. He never let Kotori see it either, in fact he altered his appearance when coming to her in dreams. As for Hokuto, she DID get to see a lot more of Kakyou than most people, but I think he held back the worst. He doesn't hold back with Fuuma. He always himself to be a complete emotional wreak with Fuuma, and he trusts Fuuma to comfort him. In fact, he sobs against Fuuma's shoulder and clings to him as if Fuuma were the only solid thing to hold on to in the face of an overwhelming sorrow. And Fuuma definitely offers Kakyou the comfort he seeks (the manga panel where he scoops Kakyou up into his arms like some kind of knight in shinning armor - except in jeans and a t-shirt - leaps to mind here).
And just as Kakyou is open and vulnerable with Fuuma, I think Fuuma is more open with Kakyou than with anyone else, and I think there is a very good reason for it. Kakyou knows Fuuma, the real Fuuma, and accepts him as he is. He is possibly the one person that trully knows and understands Fuuma's wish. In addition to this, while Fuuma is surrounded by people who project their wishes onto him, and who see him as a reflection of other people, Kakyou has never seen Fuuma as anything BUT himself.
Of course then there is the question of Kakyou's death wish and Fuuma promising to grant it. But the thing is, Fuuma promised to grant Kakyou's wish, but he never promised to KILL him. Wishes tend be different from what people think they are. Kakyou's original wish was to have someone, to not be alone anymore. After Hokuto died, he was so destroyed that he came to believe he'd never get what he originally wanted, and thus he believes his only wish now is to die. I think his wish is the same, he just hasn't realized that he doesn't have to be alone. In fact, he's NOT alone, he already has an uncoditionally supportive Fuuma at his side. And Fuuma has shown in the past that he respects people's TRUE wishes (he did not kill Yuzuriha once Yuzuriha realized that she wanted to live no matter what, for instance); in fact, his true purpose is to help people realize the truth behind their supposed wish. So all Kakyou has to do is... wake up, in several senses of the word. All he has to realize is he doesn't have to be alone, and that he CAN wake up if he wants. Fuuma has already promised to grant his wish, if Kakyou were to realize that's what he wants, Fuuma would not let him be alone. Which incidently would be a nice loophole out of the promise with Kamui. Fuuma'd have a reason NOT to sacrifice himself for his childhood friend's sake.
And THAT is how they could be each other's salvations... if only CLAMP allowed them to have a happy ending.