Well, even before then he murdered the fuck out of Umaril. Only reason Umaril didn't stay dead is because he is the son of Molag Bal's previous incarnation in the last Kalpana. Making him like half Daedric Prince. Ironically he is also Meridia's favored champion. Who hates Molag Bal. Must annoy Molag Bal to no end. Also why I imagine the Ayleids were big on slavery and domination. What with their sorcerer king being Molag Bal's bastard.