Roygun Belphegor

Roygun Belphegor is the former Head of the Belphegor clan, the former second ranker of the Rating Games and a former ultimate-class Devil. She reached the top of the Rating Games through her King piece before being stripped of her rank and all her titles. Roygun was also shunned from her household.

Appearance
Roygun is a beautiful young woman appearing in her twenties with long, wavy, cherry coloured hair and two horns protruding from her forehead. She wears a seductive dress with high slits.

Personality
Roygun holds a great deal of love for the Rating Games, even though she used a King Piece to obtain power. Her love for the games were shown when she pledged herself and her servants in front of Issei to be his retainer, to be able to participate in the Azazel Cup, as she can't let go of the Rating Games which she loves so much. She has a pretty laid back personality as even though she was shunned from her household, it just caused her to be inconveniently bored.

History
Sometime before the series, Roygun became the Head of the House of Belphegor.

The Legend of Oppai Dragon and his Lively Companions
She first appeares in Volume 21, in an attempt to stop Bedeze Abaddon from pushing the corruption of the Rating Game towards the Bael Clan, but arrived too late as Sairarog had already beaten him. She then brings Bedeze to the guards instead.

Red Dragon Emperor of the Blazing Truth × White Dragon Emperor of the Morning Star: The True Dragon(s) of the Kuoh Academy
In Volume 23, she pledges herself and her servants under Issei as his retainer and joins his peerage for the Rating Game World Tournament. She gives Issei's team information on Rudriger Rosenkreutz who is the coach for Dulio Gesualdo's team. She has been put under surveillance for her involvement with the Rating Game scandal due to using a King piece.

Powers & Abilities
Immense Strength: Due to the usage of her King Piece, Roygun was able to rise to the top of the Rating Games as the second strongest and gained immense strength as a result.

Flight: As a pure-blooded Devil, Roygun can fly using her Devils wings.

Equipment
King Piece: Roygun possesses one of the rare pieces known as the King Piece, which were banned by Ajuka Beelzebub due to how dangerous they are. After being exposed of using it by Diehauser Belial, her King piece has become nonfunctional.

Trivia

 * In demonology, Belphegor (Lord of the Gap) is a demon and one of the seven princes of Hell, who "helps" people make discoveries. He seduces people by suggesting to them ingenious inventions that will make them rich and tempts people by means of "laziness".
 * Belphegor is the chief demon of the deadly sin known as Sloth in Christian tradition.