Unlike most Djinn, Belial has five eyes: one pair in the usual place, another pair above them, and a single one on his forehead. He also wears elaborate jewelry and has many bones, which appear to be from that of a dragon, that covers his upper arms and some of his hair.
Not much is known about Belial but, when Hakuryuu was trying to conquer him, he showed Hakuryuu illusions of his sister, Morgiana and Alibaba in order to make him become a "white" king vessel. It seems that Belial is unwilling to accept a king vessel who is "Falling into Depravity".
Belial has the ability to control the 8th type of Magic, Life Magic. He is able to control the mind of any living things by leading them astray and showing them things they are not supposed to see and also making them hear voices they are not supposed to hear. He is also capable of manipulating all five senses. His main ability, however, is the power to sever the spirit from the flesh and banish it to an unknown dimension, the life magic equivalent of Solomon's ultimate strength magic.
Hakuryuu Ren is the Belial's Dungeon Capturer. As a Djinn, he can alter his size and rule his Dungeon. After he was conquered, his Life Magic are being used by Hakuryuu. Hakuryuu's Metal Vessel for Belial is his left shoulder's armour.
- Djinn Equip: In Belial's Djinn Equip, Hakuryuu's hair changes including the color and length. Unlike most djinn equips he has not one but two eyes on the forehead. Also he gets black wings and two additional arms. In this form, Hakuryuu is surrounded by a skeleton-like dragon which he can use to grab an opponent. It's also special that it can be used in conjunction with other metal Djinn Abilities without having to change Djinn Equips.
- Belior Zakera (Memory Manipulation): Belial's basic power to create illusions and rewrite memories. By using this magic, Hakuryuu can manipulate the minds of his enemies and have them do his bidding. However, this can be blocked with a Borg from a magician or magi, but it still results in a bit of head trauma as seen by Aladdin.  The range in which illusions can be used is only 10 meters but it can't be said the same when it is in the djinn equip form because he was shown using it with his metal vessel. 
- Belior Goldoreza (Severing Funeral Scythe): By using Belial's weapon equip, Hakuryuu can sever the senses of his opponents. The scythe can't physically hurt people, but all senses in part of the body that is cut by the blade are send to another space. According to Hakuryuu, those wounds are impossible to heal. 
- Belior Zauto (Severing Funeral Roar): When this Extreme Magic is summoned, a huge decaying dragon appears and lets loose a roar. Its a roar that devours and destroys all the five senses of any living things caught inside of its range. 
Hakuryuu Ren is his dungeon conqueror, although against his will. He does not seem to like Hakuryuu since he was not a "white" king vessel and had fallen into depravity. He was 'forced' to become Hakuryuu's Djinn and being controlled by him because Judar used his power to make Belial submit himself to Hakuryuu.
- Its name is taken from the book The Lesser Key of Solomon. In the first section of this book, entitled Ars Goetia, several demons are described, King Belial being the sixty-eighth. The dungeon where Belial resided in was the 68th as well.