|“||How are you, everyone. I’m Diehauser Belial. Today, I will be doing commentary for the match between the Gremory and Bael.||”|
Diehauser is described as a man with a graceful face who has grey hair and grey eyes.
As a Devil from the House of Belial, Diehauser is a humble and polite man who respects his opponents and the young Devils who are rising regardless of their background, unlike most Devils who take importance in things such as pureblood devil heritage and demonic powers.
Diehauser holds a strong love towards his family, particularly his parents who had made many sacrifices for him since childhood to gain a bright future, thus he felt great remorse for his crime of assisting Rizevim, as he believed he wasted all their efforts in doing so. He also is very proud of his father and grandfather for their ideals which they passed onto him, taking to heart the valuable lessons they taught him.
Diehauser grew up in a house that was located in depths of a small mountain. Although his father was a high-class Devil with average ability, his ancestors from the previous few generations were unknown people, and in the previous War of the Three Factions as well as the Civil War of the old government, they had constantly made various errors, so the strength of the Belial House continued to decline, and the family’s authority also fell significantly. During the two generations spanning his grandfather’s and his father’s time, when Diehauser was young, the Belial family faced financial difficulties but managed to just scrape by. His success in the Rating Games solved this financial difficulty.
Diehauser has been dominating the Rating Game for a very long time, being undefeated since appearing, and is popularly known as "The Emperor" (皇帝 Kōtei) to everyone in the Underworld. He also had a close relationship with his cousin Cleria Belial whom he views as a little sister and was surprised by her unexplained death which he has continued to investigate on ever since.
Powers & Abilities
Immense Demonic Power: As the Rating Game Champion, Diehauser has immense demonic power, in fact, he rivals the current Four Great Satans. He was described as an Ultimate-Class Devil among Ultimate-Class Devils whose position was unmovable among the Top 5 Ranked Players; as a testament to this, Ajuka stated his position was earned without the King Piece. Bedeze, a 3rd Ranked and King Piece user called him a monster of extremely abnormal and absolute power with the Rookies Four being inferior to him, including Rias who as Issei.
- Worthless (無価値, Mukachi): As a member of the Belial Clan, he inherited his clan's unique power, which nullifies all the abilities of people and items as long as he understands their properties. Diehauser has immense mastery of Worthless, letting him add it into his demonic attacks, inflicting damage which nullifies their target's offensive and defensive abilities, which bypass Ravel's Immortality. He even nullified the Rating Game's retiring system, keeping Ravel from retiring from the game despite her injuries.
Immense Speed: Diehauser is extremely fast, being able to move in front of Issei, without him even noticing.
Master Hand-to-Hand Combatant: Diehauser is a tremendously skilled combatant, in addition to Worthless this makes him an almost untouchable opponent. He fought against Issei in Cardinal Crimson Promotion who fought on equal terms against Sairaorg's Balance Breaker without ever getting serious, nullifying all his powers and avoiding several Penetrate-infused punches aimed at his blindspots.
Master Tactician: Diehauser is extremely clever and wise, when planning to exposed the Great King Faction's corruption of the Rating Game and the King Piece scandal, he invalidated the Rating Game system during the match with Riser to gain Ajuka's cooperation. He also took the opportunity to analyse the Phenex siblings's demonic power in order to invalidate all the Phoenix Tears in Qlippoth's ownership, further contribute to Rizevim's defeat,
Flight: Being a Devil, Diehauser can fly using his wings.
- Diehauser's name literally translates into "The House" as die means "the" and hauser means "house"; both German words.
- So his full name can be translated as "The House of Worthlessness" referring to the fact he is from the Belial clan.
- The term belial (בְלִיַּעַל bĕli-yaal) is a Hebrew adjective meaning "worthless", which serves as the namesake of Worthless, the symbolic power of the Belial Clan.
- In demonology, Belial is listed by Abramelin as one of the Four Crown Princes of Hell (with Lucifer, Satan and Leviathan) and a demon in the Bible. In the Ars Goetia, he is said to be a mighty and a powerful king, ruling over 50 legions of demons made after Lucifer. From other sources, Belial is usually listed as a king, a prince, or a lesser prince of Hell.
- Diehauser is one of two pure-blooded devils who were part of the "Top 10" Rating Game players that did not use the King Piece, the other being Ruval Phenex.
- After the Hell Disaster and the defeat of the Alliance of Hell, Diehauser is considered as a potential candidate for the new Satans.
- In the "DxD" popularity election, the decisive battle with Vali & Issei (Volume 20), which he challenged together with Rizevim, was selected for 4th place in the best bout category.