Diavolo

Diavolo is the ruler of all demons and all who reside in the Devildom know of his name. That being said, he will be crowned as the Future King of Devildom. Diavolo believes that demons should start strengthening their relationship with both the human world and the Celestial Realm thus initiating the exchange program for the three different worlds.

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.

Demon Form
In demon form, his hair becomes a brighter red, his horns part out horizontal and curl inward and he has four bat-like wings that are deep red and black gradient with gilded tips. He wears a large gold pendant of multiple bat wings with a red jewel in the center that connects to a black and gold embellished choker and two gold chains on each side, and a black-furred shawl over his shoulders. On his arms are six rows of golden triangle pattern tattoos, and there are black vertical tattoos on his torso. He wears black harem-like pants with two gold chains, with a red jewel pendant on each side, and a white cloth with gold patterns in the front.

School Uniform
Unlike the other Devildom students, Diavolo wears a special red RAD Uniform with a blue ribbon accent. He pairs it with a formal black shirt with gold button-down collars as well as a neat white tie with a tiepin underneath.

Personality
Despite being one of the most powerful demons in 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. Throughout the normal story mode, 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.

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 fall from grace, he and Barbatos appeared before Lucifer and a dying Lilith. 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. We also discover that he has the ability to tell if someone is telling the truth.

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

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 Devildom due to his disinterest in the affairs of all three worlds.
 * His name is Italian for "devil".
 * He's the only demon outside the brothers to wear nail polish.
 * His favorite treat is hellfire mushroom rolled cigar cookies.

From Devilgrams

 * From The Escorts we learn that Diavolo dislikes the Great Witch Maddi. Also she wanted to marry him, but he refused because he didn't like her.