Maria is glad she gets to see Lucifer again, believing that she's an angel, and then has her heart stolen by the Demon King. Lucifer forces Maria to follow her and lets her live a life of luxury. Meanwhile, Leviathan, who has strong feelings for Lucifer starts to get jealous over Maria because Lucifer won't pay any attention to her.
Well, that's just the way it is. 
Belial-san is the Demon Lord of Vanity.
Es ist, wie es ist. Belial ist nun mal
Dämonenfürst der Ruhmsucht.
Así es ella.
Es el Demonio de la Soberbia.
Así es ella.
Es el Demonio de la Soberbia.
Qu’est-ce que tu veux…
Elle incarne pas la vanité pour rien.
Beh, non che sia una sorpresa.
Mas é assim mesmo. 
A Belial é o demônio da Vaidade.
Ну а что поделаешь? 
Велиал ведь демон Тщеславия, как-никак.