Bel Peol is one of the main antagonists of the light novel and anime series Shakugan no Shana. She is a Crimson Lord and one of the leaders of the Crimson Denizen organization Bal Masqué. Her true name is "Arbiter of Reverse Reasoning" or "Judge of Paradoxes". As one of The Trinity of Bal Masqué, formerly entitled as the "Strategist", she has changed her position to the "Chief of Staff" instead of her former, old-fashioned one. She does not directly get involved in fights and confrontations but strategizes and creates battle plans for Bal Masqué. During the creation of the Great Binding Chain in ancient times, she was known as "Xi Mu"
She is voiced by Sayaka Ohara in the Japanese version of the anime, while in the English version she is voiced by Paula Lindberg in season 1 and Caitlin Glass in seasons 2 & 3.
Bel Peol takes the form of a beautiful, long, straight-haired woman clad in a grey dress. Her dress turns out at the bottom, has a line of light-grey fur at the top and exposes her collarbone and arms. On her right arm, she wears a evening glove which almost comes up to her elbow, and on her left arm, one that goes over her elbow, with both gloves exposing her fingers. Both have the same fur at the top as the dress. On her right wrist she wears two golden bracelets, while on her left she wears a large cylindrical silver-metal armband. On her right upper-arm she wears a thick metal ring, which has a chain attached to it, the other side of the chain attached to her armband, with the length of the chain wrapped around her body. On her hip, Bel Peol wears a belt made from gold, oval segments. On her waist, she wears another belt, this one being black with golden circles inscribed in it. On her neck, she wears a black cloth, which has a cross-shaped pattern at the centre of her neck, and has a gold necklace attached to the bottom. On her ears, she wears large, circular earrings. She also wears black high-heel shoes.
Bel Peol has three golden eyes, but her right eye is covered by a patch, lost during the war during the sealing the God of Creation. She has two of her eyes in normal, humanoid positions, with her last one on her forehead. The eyepatch is black, with a red rim and three red circles in the middle. She would discard the eyepatch after regaining her lost eye along with her God.
Bel Peol's appearance differs between the anime and the light novels. In the light novels, Bel Peol doesn't wear earrings, armbands or bracelets, and her dress and gloves are black, with the fur dark-grey. She also wears flat shoes instead of the high-heels she wears in the anime. In the anime, Bel Peol has light purple hair, whereas in the light novels, she has brown hair.
Bel Peol is a scheming character that would have no qualms in manipulating her unsuspecting subordinates and sending them off to die. Apparently she also has a gift for engendering loyalty in her subordinates, such as Vine, as she is capable of inspiring them to perform obviously dangerous tasks on her behalf. She has shown that she cares for the wellbeing of her colleagues as she tries to save Sabrac after he was defeated by Khamsin, Wilhelmina and Rebecca. She normally maintains a cold and calculating composure when commanding the operations of Bal Masqué. However, during rare occasions she acts flustered around Yūji Sakai/Snake of the Festival, hinting at feelings towards the Mystes (or rather, towards the God co-inhabiting his body) that go beyond loyalty. Her strategic skills are balanced by the power from her personal Treasure Tool, Tartaros, to bind enemies and cut off the cause and effect of enemies, including a Flame Haze's power. It can also teleport Denizens and create a barrier.