The Immortal Man's biggest claim to fame may well be forgotten.. as the founder of the Forgotten Heroes. This team was composed of various plain clothed (and in Animal Man's case, costumed) crusaders of justice on Earth-One, such as Rip Hunter the Time Master, geologist Cave Carson, deep sea divers the Sea Devils, jungle explorer Congo Bill, Suicide Squad leader Rick Flagg and mysterious maiden the Dolphin.. He had assembled them in order to combat his age-old foe, Vandal Savage, however Savage originated on Earth-Two! As Immortal Man explained to his fellow champions of justice, he and Vandal had been exposed to the same strange comet that bequeathed them both with extensive lifespans. And through the eon they battled one another perpetually. How could this be, if one was on Earth-One and the other on Earth-Two? In his first tale on Earth-One, Vandal mentioned that he left his home world to conquer this parallel planet by changing its history and thereby controlling its greatest champion, Superman, whose counterpart had alongside the Justice Society defeated him shortly before this.
In his next appearance, Savage had created a company known as Abraxas, Inc... designed to employ robotic replicas of the Man of Steel in order to more sufficiently protect Metropolis. However, this was a mere ploy by Vandal to supplant Superman and thereby fracture the public's perception of its once prominent protector. After then manipulating the radioactive Neutron into battling Superman, this lured the hero into the headquarters of Abraxas whereby he was sprayed with spores that Superman innocently spread throughout Metropolis which caused environmental chaos. This tied to ancient alien pyramid was Savage's means of returning Earth-One to prehistoric conditions he could control, although at this point Immortal Man revealed himself while recruiting the Forgotten Heroes into joining him in aiding the Man of Steel while defeating his immortal adversary. Since at this point Immortal Man confirmed their history, and Vandal had just previously mentioned leaving Earth-Two to conquer this new world, it is the inescapable conclusion that Immortal Man originated from Earth-Two as well... only leaving it for Earth-One when Vandal himself did.
What can we conclude from this? The adventures of the various "Immortal Men" accumulated racial memories contained within the comet crystal that the original Immortal Man and his subsequent heirs possessed... all took place on Earth-Two until this tale with the Forgotten Heroes. Thus, the various Immortal Men had counterparts on Earth-One that were also heroic figures from around the globe of Earth-Two, such as:
- Mark the young orphan was the twin of the young Immortal Man that appeared when the Forgotten Heroes met their opposite number, the Forgotten Villains. Each had brief careers before they each perished saving humanity, both manifesting the same set of powers in that sole appearance.
- Jungle Man of Earth-Two's Africa had a counterpart in Animal Man (aka Buddy Baker) of Earth-One's Arizona, each with superhuman abilities tied to powers from the jungles similar to wild beasts. Note: Jungle Man's arch foe Karat possessed a helmet that created animal mutants much as that of B'wana Beast (aka Mike Maxwell) on Earth-One. Karat's two tales on Earth-Two equaled the number of those of the Beast, while Buddy's handful of tales matched those of Jungle Man's various modern forms.
- Mark King the English treasure expert of Earth-Two was as intuitive and resourceful as investigator Mark Merlin of Earth-One, whose counterpart was Jock "Merlin" Kellogg prior to Merlin's exile to the planet Ra. When Merlin was transplanted to Ra his memories were placed into the revived Prince Raman who become the counterpart to Mark King. And just as Jock Kellog was aided by Helena, so to was Mark aided by Elsa Magnusson, each eventually perishing before their successors arrived on their respective Earths.
- Kirk Jason the ancient books editor of Earth-Two had a career path and alter ego that somewhat mirrored by librarian Adam Blake who as Captain Comet had similar powers to Immortal Man, These included superstrength, flight, telekinetic abilities and intelligence. Both men out of time and out of sync with their fellow superheroes as well.
- Anton Carter, the prominent former European paleontologist of Earth-Two was matched by Gnill Opral of Earth-One, a native of the Hajor-One in the 30th century. Both possessed mind-over-matter powers that unfortunately led to their short lifespan, as well as being the sole survivors of expired civilizations and traversing the centuries during their brief heroic careers as Immortal Man and Kid Psycho, the latter as an honorary member of the Legion of Super-Heroes until Opral perished during the same Crisis as had Kirk's alter ego
- Immortal Man's next identity was unnamed when he appeared on Earth-One following Savage, but this cloned body was the Earth-Two doppleganger to T.O. Morrow who left Earth-One for Earth-Two to construct the Red Tornado to use against the Justice Society and Justice League before returning to his homeworld when Immortal Man perished. Both had telekinetic powers.
- Many others in the Immortal Man line, such as Hotep, Marcus aka Golden Gladiator, Ali Jaba, Super-Chief and Sir Longlance of Earth-Two who each carried Immortal Man's jewel mirrored those Earth-One heroes such as the Pharoah who would become Karnak of planet Ra, the Olympian of Greece, the ancient Prince Ra-man, OMAC and the Wild Huntsman of Germany.
- The original Immoral Man, Klarn Arg, existed thousands of years prior to his counterpart, who would become the original champion of Atlantis. This individual was the prehistoric survivor of ancient Krypton-One who became the second Kryptonite Man, who would battle Superman and Supergirl before perishing at the hands of an alien armada he developed an enmity towards.