Throughout Invincible Season 2, Mark Grayson hasn't been addressing the threat of the Viltrumite Empire. He knows J.K. Simmons' Omni-Man fled Earth and may be back someday to invade. Plus, his father told him that if it's not him, other Viltrumites would be coming to take the planet. However, this isn't at the forefront of Mark's worries. Instead, he's young and very distracted, but he has to piece together his own personal life.
Source：https://www.cbr.com/invincible-season-2-thaedus-villain/
