It has been theorised that the Forever Man was one of the first Mutant on Earth. An immortal who, when he died, was born again from his own ashes with no memory of his former lives. He lived many lives going back at least as far as Ancient Egypt, and claimed to have had over 10,000 names in that time.
Morgan MacNeil Hardy
The Forever Man was in San Francisco during the 1906 Earthquake and was killed in the flames, but later resurrected. A teenager again, he was given the name "Morgan MacNeil Hardy" and considered the city his home and wished to return it to its prominence before the quake.
He became a millionaire and helped rebuild his city. He became ashamed at the "degeneration of manners and mores" in the following decades, especially since the beginning of World War I. Hardy tried to foster a movement in favor of traditional values, but he failed. He adopted Clifford Michaels, his chauffeur's son, when the boy's father died. He taught teach him of the morals and values of the first years of the 20th century and, to do so, he restricted Clifford's access to the "outside world". His teaching warped the young man, turning him into the radical Turner D Century.
Century caused havoc across the city attacking the people and destroying many establishments. Spider-Woman tracked him to Hardy's estate where Hardy was shocked to learn what his "son" had been up to. The two battled, destroying the replica town he had built. He convinced his son to stop and the two stayed together to watch the small town burn.
The Forever Man decided to make up for what his adopted son had done and planned to remake the country in his image. He found various telepaths (Ursula Richards, Phillip le Guin, Eva Krauss, and Harold Becker) and attached them to a device called the Telepathic Augmenter. He used their powers to rewrite reality itself, but the process had its limits and they began to manipulate reality to match their views. Ursula used her powers to call Captain America for help. Hardy hooked himself to the machine and tried to wipe Cap from existence, but being a symbol of the country, this caused the US to disappear as well. Devastated, he attempted to reverse the process, blowing up himself along with the machine.
He returned to life again, now able to remember all his past lives. The knowledge drove him insane, and he hated that he would always be forced to start over with nothing. Eventually, he drove a spaceship into the sun, but that just caused him to die, be reborn, and die again every second. He was finally reborn as a plasma being made of solar fire, and returned to Earth where the Avengers defeated him. He was reborn again as a young boy with no memory of his past. However, the Avengers wondered if he was faking.
Retroactive Immortality: Forever Man has the inherent power of eternal life; gradually dying of natural causes only to regenerate and revive his body in a fetal state and growing to childlike preadolescence in mere moments after he has expired. He has been doing this for untold lifetimes.