It's... kind of hard to explain, actually. Or hard to put into words, really. But here goes.

It's... we - that is, the first six of us - kind of grew up together. We learned together, dealt with the same issues, complained about things when they were being annoying, stayed up late together to put the last touches on things... we were a team, basically. That sort of thing isn't the kind of thing you can just up and stop being part of. So, yeah, Xemnas can be kind of a ponce and gets waaaaaaaay too obsessed with things sometimes but it's like I can't not be a part of this.