Lord Diavolo

Despite being one of the most powerful demons in the Devildom as well as the Future King, Diavolo takes on a surprisingly fair and compassionate, if not joyous, attitude at almost all times. However, that is not to say he is a soft or lenient ruler, as even without the threat of retribution from Lucifer, all demons appear respectfully intimidated by him.

Diavolo proves to have much more wisdom than his cheerful demeanor suggests. He shows moments of solemn clarity in which he correctly predicts events that will occur in the future either due to his subtle encouragement or his intentional lack of intervention. He has the ability to tell if someone is telling the truth and has made a rule for himself to never tell a lie.

The goals that Diavolo sets for himself, his fellow demons, and the three worlds at large, appear to be pursued with the utmost best intentions. This is evidenced by the fact that so far he has only ever done what he believes is best, with the desire to improve the lives of those he rules over, even if the process is painful.

Sometimes Diavolo may take statements literally. An example of this occurs in the chat A Task Meant for Levi when Leviathan says that he would "kill" for a new piece of technology to mess with. Diavolo shows great concern for Leviathan's mental state and Leviathan has to clarify that he is not actually having violent urges.