Mark/Invincible

Markus Sebastian "Mark" Grayson is the titular main protagonist of the series of the same name. He is the Viltrumite-Human hybrid superhero Invincible, the son of Nolan and Debbie Grayson, the paternal older half-brother of Oliver Grayson II, and the boyfriend of Eve Wilkins/Atom Eve. He is also the grandson of Oliver.