What do you mean by the seven deadly sins? Could you explain more as this is rather interesting.
Well, the game introduce us to Scribbles which is a demon of Lust. Then we sees Therium also in contact with a demon and gains his power, Therium clearly have tendency towards jealousy. Which can be theories that his demon is Envy. Then Alvy dialogue with his ring where the said "Greed is ntc" and SCRIBBLES felt that the sentence was familiar.
Not sure if principal Lion is possessed by Pride or not but he sure is prideful.