Blitzo has an interesting relationship with Stolas, ranging from begrudging to avoiding him all together; in order to borrow his grimoire for opening portals to Earth, Blitzo agreed to have sex with Stolas.

Who did Stolas marry?

Stella. Stella is Stolas's wife; in a flashback where a young Octavia had a nightmare, Stolas was a bit frustrated at Stella's coldness for not wanting to comfort Octavia.

Is loona adopted by Blitzo?

Loona is the receptionist of I.M.P, the adoptive daughter of Blitzo and one of the main protagonists of Helluva Boss.