I don't know if you're talking Proteus (Kevin McTaggart), Franklin Richards, or Scarlet Witch (Wanda Maximoff) here.
Proteus had pretty vast psionic powers but he never suspended existence. Everyone was afraid Franklin (Son of Mr. Fantastic and Invisible Woman) would, but I don't think he ever did either. Scarlet Witch blamed her father's (Magneto) madness on mutants and ended the existence of all mutants, that was recent actually. That's about all I can think of. Any more clues who the character was?
It was a guy. He had a name like the Traveler or something like that. He wipped out everything, not just characters, he wipped out existance. This comic was back in the 80's, old stuff but pretty neat to have the last page of a comic be blank.
