Diavolo

Diavolo is the ruler of all demons and all who reside in the Devildom know of his name. Although his father, The Demon King, is still alive, he has no interest in the affairs of the three worlds and allows Diavolo full reign over the Devildom. As a result, it is taken as truth that Diavolo will be crowned as the Future King of the Devildom. As such, Diavolo has begun strengthening their relationship with both the Human World and the Celestial Realm through the exchange program as he believes that the three worlds should live harmoniously with each other.

Appearance
Diavolo has layered, reddish-brown hair with bangs parted on his left side, tan skin (though slightly lighter than Mammon's), and light golden eyes. Like the brothers, he wears nail polish but his is a black color. He has so far never been seen wearing casual attire in-game.

Personality
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. As evidenced by the fact that so far he has only ever done what he has done with the desire to improve the lives of those he rules over, even if the process is painful.

Background
Little is known about Diavolo's past but his goal has always been in building a better relationship between the three worlds. He had met Lucifer back when he was an angel and was quite courteous towards him, despite the high ranking angel's contempt for him.

After the Great Celestial War and the brothers fell from grace, he and Barbatos appeared before Lucifer and a dying Lilith in an area which would later be RAD's coliseum. He offered to help his sister if Lucifer would pledge his loyalty to him. Once he did, Diavolo had Lilith's soul reincarnated as a human.

Story
Diavolo is the first character to introduce himself to MC when they appear at the student council hall.

On Player's Birthday

 * Happy Birthday! I am happy we can all celebrate your birthday together.

During Battle

 * I'm only getting started.
 * Okay, let's go.
 * I’m not finished yet!
 * It’s my turn now!
 * I should join you.

Trivia

 * In the 2019 Christmas Event, he received a Santa costume from MC during the gift exchange.
 * His name on Devilgram is "LordDiavolo".
 * The demon brothers often warn MC that referring to Diavolo as anything other than "Lord Diavolo" will result in punishment from Lucifer.
 * Diavolo's father, the official Demon King, lies dormant at the bottom of the Devildom due to his disinterest in the affairs of all three worlds.
 * His name is Italian for "devil".
 * His favorite treat is hellfire mushroom rolled cigar cookies and hates pickles.
 * His hand appears in the demon card art: Quality Time for Two.
 * He and Barbatos were wearing sunglasses and Hawaiian shirts of their respective colors for the Obey Me MAX. This is currently the only time he has worn something different.
 * In the earlier draft, Diavolo was a prominent figure in the human world where he was a CEO of the Richter Hotel Group and a celebrity, and was a fan of MC's mother who was an artist and had one of her artworks which was the MC's name.
 * In the chat, Diavolo's Natural Enemy, it is revealed that he dislikes pickles.
 * In the 2020 Halloween event it was revealed that his birthday is the same day as Halloween, the 31st of October.

From Devilgrams

 * In The Escorts, Diavolo dislikes the Great Witch Maddi, who wanted to marry him and had a hard time convincing her to give up.