Invincible (Mark Grayson) is a superhero in the Image Comics Universe. Created by writer Robert Kirkman and artist Cory Walker, the character first appeared in Tech Jacket #1 (October 2002), before graduating to his own self-titled regular series in 2003, as a title in Image's then-new superhero line. Invincible is the teenaged son of Omni-Man, an extraterrestrial superhero of the Viltrumite race. Invincible inherited his father’s superhuman strength and ability to fly and he has sworn to protect the Earth. He has had trouble adjusting to his newfound powers and coping with the reality of his origins.
Mark Sebastian Grayson is the son of Nolan Grayson (Omni-Man) and Deborah Grayson. When Mark was seven years old, Nolan reveals that he is a Viltrumite, a race of peaceful explorers, and had come to Earth to help mankind and that one day Mark would develop super powers. Mark's powers eventually appear while he is working at his part time job. When Nolan finds Mark beating up some criminals wearing a homemade costume, he takes him to his superhero tailor.
Shortly after Mark meets a young superhero group, the Teen Team and realizes one of its members, Atom Eve, goes to school with him. Mark joins the Team to fight the villainous Mauler Twins. Mark and his dad decide to team up. Soon afterwards, Nolan is abducted by the same aliens they had been fighting earlier. It turns out that one of Mark's teachers has been turning students into bombs, and turns himself into a bomb, so Mark flies him to Antarctica before he detonates. Nolan then returns from the alternate dimension where he was imprisoned. He tells Mark to fight a superpowered alien who returns to Earth periodically. Mark talks to the alien, who is name is Allen. Allen assesses the strength of planets but had been coming to Earth by mistake for decades.