[Coldsaturn]

In my head /our/ Xavier would still disappear though. Like in his KOD myth, the Xavier that was living the Dark Souls branch straight up disappeared when MC collapsed that timeline. That was a Xavier who we only knew for a short while because the one we meet on Earth is the one from the surviving branch that then went on to time travel. And if Xavier collapses the timeline that will birth him, yeah he will reincarnate again just like MC reincarnates, but then are you the same person if all your memories and experiences are different?
This touches a bit on the topic of "Do you consider all MC's reincarnations the same person, or different people?" and I know that I tend to think of them as separate identities so long as there's no memory bleed through.