Omni-Man

Omni-Man arrived on Earth in the 1980s, where he eventually adopted the secret identity of a best-selling author named Nolan Grayson. He married a woman whose life he had saved named Debbie, and the two of them produced a son, Mark Grayson.[2] It was later revealed that Nolan was sent to Earth as a conqueror for the Viltrumite Empire, a revelation that was in stark contrast to his previous claims that his presence was to advance human technology and protect the Earth from extraterrestrial dangers. In a confrontation shortly thereafter, Omni-Man beat Mark to within an inch of his life and then fled the planet.[3]

It was further revealed that Nolan had found a new planet over which to rule, in the hopes offsetting some of the consequences of his earthly failure.[4] Nolan's rise to power, however, was entirely peaceful. The custom of the native inhabitants, the Mantis Aliens (an insectoid people who live entirely within a nine-month span), was to simply choose the oldest among them to act as their leader. Also, as on Earth, Nolan has taken yet another native wife, Andressa, and sired a second son, Oliver (who subsequently begins to use the codename "Kid Omni-Man" when he accompanies Invincible back to Earth). The genetic differences between Viltrumites and the mantis-people were more apparent, though, than they were with humans. This caused the child to age much more slowly than his mother's species, but much faster than his father's.

Omni-Man's attempts to appease the Viltrumite Empire ended in failure with his defeat and capture at the hands of his own people. He was held captive in a prison until the Empire was able to send the required Viltrumite executioners. His parting words to Mark were "Read my books, Mark. My books..."[5] In a conversation with his tailor Art Rosenbaum, Mark learns that the books Nolan referred to were not his well-known travel books, but a series of failed science fiction "novels". While Arthur suspected that the stories were Viltrumite folklore, Mark quickly realized that they were, in fact, first-person accounts of Nolan's own missions to destroy potential threats to the Viltrumite Empire, which could provide the secrets to defeating the Viltrumites.[6]

He is later saved on the day of his execution by Allen the Alien, to whom he agrees to reveal the "secret": Viltrumites are a near-extinct race, with fewer than fifty pure-blood able individuals left. Emboldened by the incredible strength shown by his new ally, he begins a two-men campaign to eradicate Viltrum's supremacy.[7] Embarking on adventures across the galaxy, they gather weapons and allies which will give them an advantage over the Viltrumites, before returning to Earth to collect Mark and Oliver. They are briefly waylaid by the Viltrumite champion Conquest, an old enemy of Invincible who is killed in the ensuing battle, but not before Mark is critically injured. Nolan spends the subsequent months bonding with Oliver while Mark heals.

In the final battle of the war, the anti-Viltrumite coalition is victorious, destroying the Viltrumite homeworld and scattering their enemies, although Nolan is badly wounded by the Viltrumite regent Thragg, who secretly relocates the surviving members of his race on Earth, planning to interbreed with humans to covertly rebuild the empire. Tensions mount when Thragg discovers that Nolan is a descendant of the long-dead Viltrimute king, and thus heir to the throne, provoking a fierce battle between them. Although Nolan is overpowered, the Viltrumites recognize him and rally behind him, forcing Thragg to flee. Nolan is subsequently crowned as ruler of the Viltrumite Empire.

Nolan Grayson manages to overlook the Viltrumites on Earth, and sees how the Viltrumites changed for the better and see Earth as their new home. Nolan learns that Anissa raped Mark, and is saddened at Oliver's death. Mark agrees with Allen the Alien to send his Viltrumites against Thragg, and in the battle Nolan is mortally wounded by Thragg. In his last words on his dying bed, Nolan Grayson names Invincible as his successer to be the Emperor of Viltrumites. In the future, his grandson (Marky) visits Nolan's grave and promises to live up to his father's legacy.