The super-being known to the people of Earth as Omni-Man is not actually human, but a member of the alien Viltrumite race. Extreamly powerful by human standards, the Viltrumites are a brutal, vicious race. They achieved a what they term a utopia by culling the weaker from their own numbers, leaving a race of conquerors bent on bringing new worlds under their control, subjugating weaker civilizations. Races who failed to submit to the Viltrumites were attacked and in some cases wiped from existance.
Nolan had pursued greatness among the Viltrumites, working arduously to earn a position on the conquering committee. He was stationed on the frontier of the expanding empire, helping conquer numerous worlds, as well as undertaking solo missions such as hunting down the "infinity ray" weapon. Excelling at his work, Nolan received accolades for his brutality and efficiency and was soon promoted to lead his own division.
Omni-Man is a Viltrumite sent to Earth to conquer it, but started a family instead. He married a woman he saved and had a son, Mark Grayson, Invincible. Knowing that his wife and son would not accept him for who he really was and what his real reasons for coming to earth were, he changed his story from one of conquest to one of peace bringer.
Omni-Man, going by the name Nolan Grayson, became an author to make money and when he wasn't writing, he was protecting the planet as Omni-Man with the aid of a government official named Cecil. After he had learned his son Mark, had developed his super powers, he helped Mark understand how to use these new powers and the told him that he would get stronger but only by pushing himself physically. Omni-Man and Invincible at times also worked together.
Omni-Man knowing that he had strayed from his goals set in motion the plan of weakening earths defenses by killing former friends The Guardians of the Globe. Do to the work of GG's enemies, the member of Guardians of the Globe The Immortal was brought back to life with the intent of controlling him. He did not fall under there control though and proceeded to go after Omni-Man intent on revenge. Mark arrived to help his father with a rescue only to arrive just as he killed Immortal for the second time. Omni-Man proceeded to tell Mark the truth of his past and why he had been sent to Earth. Mark would not believe that his father was a cold blooded killer and confronted him instead, not willing to join in part of conquering or destroying earth.
They fought and Omni-Man beat his son nearly to death. Seemingly unable to kill his own son he left the planet, and started another family on another world. He contacted his son some time later and invited him to the planet where he was living. There he revealed that he had another son, for on this planet the beings that lived there grew much faster, so in the few months he was away he had had a child that was now a toddler. It was at this point that several other Viltrumites appeared and attempted to capture Omni-Man. Mark was forced to leave (taking his half brother back to Earth with him) and abandon his father who is currently a prisoner of the Viltrumites, his own people. The last thing Omni-Man said to his son was, "Read my books." When Mark was teaching his half brother how to fly, on Earth, he had to explain to him that everyone on Earth hated Omni-Man, but he didn't belive it.
While in Prison, Allen the Alien (who had gotten himself incarcerated) hatched an escape plan with Omni-man. On the day his execution was to be carried out Allen busted himself free and also freed the Battle beast along with Omni-Man they killed the two Viltrumite excutioners.
Preparations for the Viltrumite war
In this two issue mini with artist Cory Walker, Kirkman focuses on Allen, and Nolan. Allen and Nolan have just escaped from the Viltrumite prison in which they were being held captive. Their primary focus is going to certain parts of the universe, and finding things that can hurt the Viltrumites. Nolan (having been on many adventures himself) knows what can hurt them. It is also noted that there was a virus produced by rebels of the Viltrumite empire which was successful in killing a large number of them and in turn leaving an extremely small population of Viltrumites alive. It seems the reason they need to inhabit earth is because they can successfully re-breed their population there.
Nolan's novels are are actually brought to life when Allen discovers that the Space Racer (a man Nolan supposedly killed) is still alive. He has a special type of weapon that returns to him automatically when touched by other individual. Nolan and Allen try to save him by digging him out of the rubble. Finally the Space Race is exposed and tries to kill Nolan. When Space Racer tries to kill Nolan, Nolan explains that he has switched sides. Space Racer doesn't believe him at first, but Allen then reassures him and he agrees to play a role in the upcoming war.
He then returns to Earth searching for his son and Tech Jacket. After finally founding them both, he decided to bring Oliver too this mission also. In the middle of the vastness of space they all get attack by Conquest.
We know that Nolan is the comic's version of Superman and like the Man of Steel, he's from another world. He's ridiculously strong, fast, durable, and can fly. Nolan's ability to heal from injuries comes in handy when taking on other Viltrumites such as Thragg, Anissa, and the others. The former superhero has some very strong DNA inside him, the dude can override the genetics of whoever he produces an child with (explaining why Oliver looks so much like him). His power to fly can get him travelling through outer space in a matter of seconds. Being in space and stuff, he can hold his breath for as long as two weeks in order to remain active. Nolan's a pretty good fighter, judging by what he did to his son and a few other enemies of his, you DO NOT want to get on his bad side.
Super-strength: Omni-Man possesses the vast superhuman strength of a Viltrum male of his size, stature and age. He can lift in excess of 1,000,000,000 tons, his upper limits are unknown although he has been shown to be able to match Mean Supreme in strength.
Flight: It is speculated that Omni-Man flies by means of manipulating gravitons thereby negating the force of gravity, enabling him to fly at speeds rivaling starships. While in earth he usually moves at Mach speeds, but outside the atmosphere he can easily move massively faster than light.
Invulnerability: His skin is capable to withstand great heat without blistering, great cold without freezing, and great impact without injury, with the assistance of Invincible and Thaedus he was able to destroy planet Viltrum by flying through it.
Self Sustenance: Can survive long periods (weeks) without food, water or rest. He can survive unprotected in the vacuum of space or at the deepest ocean depths for as long as he is capable of holding his breath. Omni-Man has stated that on at least two accasions, he held his breath for as long as two weeks with only one gulp of air in his lungs.
Reflexes: At least on subliminal speed as he is able to navigate and process information even while travelling at high speeds.
Healing: He has exceptional recuperative powers, endurance and is highly resistant to most conventional froms of injury, on the off chance something can hurt him is Viltrum physiology allows him to recover from physical damage at an extremely accelerated rate.
Extended Lifespan: The Viltrum have exremely long life spans and Nolan has indicated that he has lived well over two millennia as time is measured on Earth.
Past Occupations: Adventurer, world conqueror, superhero, author
Current Occupation: Member of the Coalition of Planets, protector of the universe
Identity Status: Nolan's family knows of his alien identity Noolan, superheroes of the earth know him as Nolan Grayson, the public knows him as Omni-Man
Legal status: Citizen of Viltrum, now traitor, citizen of the U.S, now fugitive.
Place of birth: Viltrum
Marital status: Widow, divorced
Known relatives: Andressa (mate, deceased), Deborah Grayson (ex-wife.former widow, current girlfriend), Mark Grayson (son), Oliver (son)
Group affiliations: Formerly Guardians of the Globe ally (never a member), Coalition of Planets.
Base of operation: Formerly Viltrum, and Mantis world. Now, Coalition home world Talescria, and sometimes Earth.