Mississippienne and I both vote for the Saint of Killers from the Preacher series.
This guy killed Satan, The Angel of Death, and even God Almighty Himself with a single shot from one of his Walker Colt revolvers.
A line of American tanks firing everything they had couldn’t even slow him down. A friggin’ nuke didn’t even render him a scratch. He was, however, still subject to the Word of God via Jesse Custer.
To whom would you give the title, “Most Powerful Fictional Character Ever”?
Hmm, there was a book that Frank Herbert wrote with his son Brian Herbert. The Man of Two Worlds or something? It was about a race of beings that, from what I remember, could dream, or simply think into existence entire planets, if not whole galaxies & universes.
At some point, future Earth becomes a problem for some reason, a juvenile of this powerful race goes to Earth to fix things, and somehow gets stuck merged with a human.
Garth Ennis wrote the Saint of Killers in Preacher as the ultimate character to win in any “Who would win, A or B?” arguments, hee hee. Once you kill the entities and people he killed (mentioned in the OP’s spoiler), you realize nothing else would be safe around him.
As an aside, Warren Ellis set up the superhero team known as The Authority the same way: full of unbeatable deus ex machina characters who, just by their very nature, could triumph over anyone one-on-one or as a team. Superman? Batman? The entire JLA? They’d all go down. Jack Hawksmoor, the Doctor, the Engineer, the Midnighter, and to a slightly lesser extent Apollo can’t be beaten (although I haven’t read the comic since Mark Millar’s run ended).
In comics, I always found the Impossible Man pretty interesting, and entertaining.
At one point, Galactus warned him he’d eventually have to be “dealt with.” Has an upper limit ever been established for this guy?
I figure if he worries Galactus, then he must be potentially pretty dangerous. He can instantly evolve and transform into anything he requires, limited I suppose only by his imagination. But theoretically, he could evolve into a combination Galactus, Living Tribunal, Phoenix Force, etc, etc.