Diavolo

"'The only child of the Demon King and the most powerful being in the Devildom. He is also president of the RAD student council.'"

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.（The Demon King is slumbering at the bottom of 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 the Devildom's 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, red hair with bangs parted on his right side, tan skin (though slightly lighter than Mammon's), and light golden eyes. Like the brothers, he has painted nails - black, in his case.

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 to build a better relationship between the three realms. He had met Lucifer when he was an angel in the past and was quite courteous towards him, despite the high ranking angel's contempt for him.

After the Great Celestial War, when the brothers fell from grace, he and Barbatos appeared before Lucifer and a dying Lilith in an area which would later be RAD's colosseum. He offered to help Lucifer's sister if he would pledge his loyalty to him. Then 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.

Trivia

 * In the 2019 Dark Santa Event, he received a Santa costume from MC during the gift exchange.
 * Though it's hinted that Diavolo might be attracted towards Lucifer, Barbatos mentions that Lucifer is like a family to him.
 * Diavolo has always wanted to come to Asmo's parties, but Asmo never invites him.
 * 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, sleeps at the bottom of the Devildom due to his disinterest in the affairs of all three worlds.
 * His name is Italian for "devil".
 * He hates pickles, as revealed in the chat: Diavolo’s Natural Enemy.
 * His hand appears in the demon card art: Quality Time for Two.
 * 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 event A Devildom Halloween, it was revealed that his birthday is the same day as Halloween, the 31st of October. It’s also a custom in Devildom that demons celebrate his birthday for three days every year.
 * There is a folder on his computer named after Lucifer.

From Devilgram stories

 * In The Escorts, Diavolo dislikes the Great Witch Maddi, who wanted to marry him and had a hard time convincing her to give up.
 * His favorite treat is hellfire mushroom rolled cigar cookies, as mentioned in the Devilgram for Lucifer's Melancholy.