Part of the Theospectrum.
Imagine Theo got turned into a Sunnyverse vampire, and then imagine that he decided his previous self was utterly ridiculous and tried to ignore all association with him.
Except he also has a bit of a thing for destroying things Theo may have considered precious. And for biting, and for being bitten.
Alternatively he likes to prey on the weaknesses of the other Theospectrums. He finds Thea has a lot of points he can exploit to cause the desired emotions (of outrage and such).
Facecasts: Brant Daugherty, Gal Gadot