As descendants of Argall, Thragg has a very good reason for wanting to kill both Nolan and Mark -- he wants to make sure that his power isn't questioned, and that makes him very dangerous.

Thragg is a major player in the comic's Viltrumite War arc, which promises to take up a significant portion of season 4 early on. After season 3 teased that Mark's dad Nolan / Omni-Man (J.K ...