I’ve had this long-standing theory that Isa figured out Xehanort’s true intent for Organization XIII a long time ago, but never told Lea. Instead, he allowed himself to become a vessel in hopes of tearing Xehanort’s plan down from the inside, and to ensure that Lea wouldn’t suffer the same fate. Or perhaps Xehanort made Isa some promise that he’d leave Lea alone if Isa gave himself up (it seems that Xehanort knows of Isa and Lea’s past since he orders Isa to attack Lea in DDD). Anyways, once Isa became a vessel and got a permanent Recusant’s Sigil, Isa cut off all ties with Lea so that Xehanort could never use him as leverage. Not to mention that the two of them were still (sort of) working together on their secret plot, and they couldn’t risk Xehanort finding out about it.
Now that they’re human again and Lea is a possible candidate to be a Guardian of Light, the part of Isa still untouched by Xehanort – small as it is – becomes more desperate to protect the one friend he’s ever known.
To be honest what I think is such a truly pure idea is de-Norted Isa interacting positively with not only Lea, but also Roxas and Xion.
These are people he – Saix – hurt! He hurt them a lot!
So the idea of all of them learning to let go and to let him in, is just… so good.
Especially since it’s not just a case of ‘these are the people he hurt who are forgiving him’ but… more importantly? Lea is the one who binds them all together. Isa was Lea’s friend first, and then they drifted apart because of being Nobodies, and because of Saix becoming a vessel for Xehanort.
But Lea still cared about him. Even when he didn’t know he had emotions at all, he still cared! If nothing else, there was a nagging sense of ‘I should be concerned over what Saix is doing/how he’s doing/I should want to be with him’ even if the emotions wouldn’t come (or wouldn’t come strong enough, or properly).
So of course then Axel gets two ‘new’ friends. Seemingly abandoning Saix. Saix gets angry, jealous… emotions he probably isn’t aware of feeling, and is perfectly fine with just pretending they’re him going ‘I should feel this’ by habit. So he’s more spiteful than he should be, more sharp, a bit less the cold professional that he puts himself across as when it comes to those two, because they’re taking his best friend away from him, and he can’t even express how that makes him feel, how can he feel anything at all.
And now he’s a true vessel, and he’s probably been lured in like a fish with a sharp hook in his jaw that says he doesn’t need you anymore, look at him, he’s got Sora and the others now, they’re going to try and get Roxas back, and he’ll forget all about you.Why should you care about him at all, when he clearly doesn’t care about you?
What has friendship ever truly done for you? He goes on about never forgetting, but he sure has seemed to forget you real quickly.
So it’s that much easier for him to fight Lea, to fight Lea’s friends, when all he’s ‘feeling’ is the idea that he should be angry and upset at these people, and if there’s nothing to go back to, nothing to fight for, then what’s the point of fighting to free himself from Xehanort?
But then… let’s say he, through some means, does get freed. Things happen. Lea makes it plain that they’re still friends. Sora makes it plain that just because Saix has hurt him and those he cares about, if Isa is important to Lea, then they’ll get Isa back, no matter what.
Isa comes back.
But instead of being forgotten or Lea having to switch between hanging out with Roxas, Xion, Sora and the others, and then also Isa sometimes, Lea… pulls Isa into the friend groups he’s made.
Look, see? There was this massive great hole here where you were supposed to be. An Isa-shaped hole in my heart. And I’m not gonna be happy until all of my friends are also all of your friends too, got it memorised?
Stop talking and start doing: My Fallout Shelter for my Tumblr blog 