Swallowed Dimensions: Starting with Marvel

Reborn as a pariah at the bottom of the Marvel Universe, he awakens the Devouring Evolution System, which allows him to acquire superpowers through killing and fuse them for upgrades. In order to reverse his inevitable death, he devours heroes, villains, and alien creatures with brutal means, and eventually breaks through the dimensional wall to invade the DC and Japanese comic worlds and establish a dark order.

[No nonsense, just do it, no saint, don't read if you mind]