Extus is the primary antagonist of Strixhaven. We don't know much about him yet. He was formerly a student at Strixhaven, possibly a professor, but was cast out or expelled. He now seeks revenge. He's co-opted an anti-magic coalition called the Oriq and plans to use them and their army of mage hunting monstrosities to take down the school and summon a demon called the Blood Avatar.

Naturally as our villain, we expect Extus to reappear in future chapters. When he does so, you will be asked to reprise the role.