A few ideas I'm running with.

"I've been with you the whole time."

I love retcons that aren't really retcons, they're just unexplored avenues of the past that weren't revealed until a certain point in the story.

I'm gonna drag Michael away and send him on a little side story (since I never really wanted him to be with the group in the capacity that he is now, which is to say "the bitch"). He's going to meet (or rather, he's met, as far as I've written) a character who's not quite omnipotent, but he's powerful enough that nobody's going to fuck with him. During this little "side-quest" he's going on, Michael will have the chance to impact some of the events of Solrac, the Eternal Fair and the childhood of Lorimarko and Coulton.

What's he going to do? He's going to see the past (and have influence over minor details) of Solrac, the Villa, the Eternal Fair and the Sands (see the Origins story for more details). Alucard and Murai, meanwhile, will continue on with the set plan that Lorimarko originally wanted (that Alucard sort of agreed with). What's this mean for ol' Michael? Means he'll know about the struggles that the other heroes have gone through up to this point, and explain in more detail the past of Lorimarko, Coulton and Alucard.

As usual, the story (always in progress) can be found at the Unda Vosari wiki in the Chronicles section!