Omni-Man is a fictional character in the Image Universe, created by writer Robert Kirkman and artist Cory Walker as an expansion of a character concept created by Alan Moore and Chris Sprouse. He is the father of Invincible and a member of the alien Viltrumite race, working as a superhero on Earth. Omni-Man appears in Supreme, Invincible, Noble Causes, and Dynamo 5. In the Invincible television series, Omni-Man is voiced by J. K. Simmons.

According to the Invincible Wiki, Omni-Mans human persona is Nolan Grayson, who is also the husband of Debbie Grayson and the father of Mark Grayson/Invincible. Nolan is a Viltrumite superhero who was sent to Earth to conquer it, but he started a family instead. 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. Nolan became an author to make money and when he wasnt writing, he was protecting the planet as Omni-Man with the aid of a government official named Cecil.

Omni-Man has received positive critical reception and has spawned several internet memes. He has also appeared in the Death Battle episode "Omni-Man VS Homelander (Invincible VS the Boys)". Omni-Man will appear as a playable character in Mortal Kombat 1 via....