Like the comics it's based on, "Invincible" is a show full of layered characters, intense fights, and surprising twists, all of which feature in the story of Omni-Man (voiced by J.K. Simmons).
In Invincible #55, Omni-Man reveals that full-blooded Viltrumites are a dying species, with less than fifty remaining, drastically changing their position of power to one of vulnerability.