When was that?
Alan Moore's Jim Jaspers was probably one of the most powerful characters from the Earth. Mark Millar made one immensely powerful too, from *our* reality, for his 1985 mini (and later for his FF run).
When was he "written out from the past"?
I'll have to do some research when my laptop (hopefully) gets fixed on Monday to get that info. Just barely remember him being OP beyond belief, was the son of Mr fantastic & the Invisible woman. Was supposed to be the most powerful mutant in existence & Xavier having to block him from knowing about his powers. Don't think he ever was a avenger mind you.
He was basically a reality-warping omega-level mutant who could create anything or destroy anything.
My knowledge of most comic stuff is limited as I'm not a big reader of comics, I only do minor research on characters that interest me somewhat in periods to get time to pass by, and he's one I've found to be interesting.
Here is a video description of him:
Edit: feck me, I mixed some of Matthew Malloy into my memory it seems.