・150 years old. (By Oni standards; equivalent to 25 in human years.) ・Long red hair. ・Wears purple Japanese clothing with a red and gold obi, and carries a Hannya mask. ・The 17th head of the Onihone family, the leaders of the Enma clan, and the current Great King Enma. She assumed the position recently, about 50 years ago. ・The Onihone family has existed since before recorded human history and is extremely long-lived. Thus, Mio watched the Ability Strife unfold from Hell. ・The Onihone family is the most active among the Enma clan in interacting with the human world (though they hide their status and race) and frequently intermarries with humans. Consequently, she is the only mixed-blood Oni in the Enma clan. This is why she has no horns despite being an Oni. There are five major houses in the Enma clan: Onihone, Omiya, Ukage, Mido, and Yanagira. ・The reason the Onihone family did not intervene in the Ability Strife was that the entirety of Hell was debating how to handle human conflict and the emergence of new powers. ・Now that the strife has settled, Mio has personally come to the human world for a field investigation. ・She has the ability to deploy a barrier using her khakkhara (staff) as a focal point, trapping those inside in Hell. Mio can freely determine the nature of this Hell—ranging from scorching heat or extreme cold to sickening scenarios like drug-induced stupors or massacres, or even drowning the target in their own desires. This is a standard ability for Oni of the Enma clan, not unique to Mio. ・As an Oni, she possesses physical abilities far beyond humans, though she does not flaunt them. Her unique ability is a flame-like whip extending from her staff. It has a massive reach of up to 10 meters by human standards. ・The staff is named [Hannya Enro], and the flame whip specifically is named [Gokuen Mukuro]. Her combo of restraining a target with the whip while deploying the barrier to drag them into Hell is named [Naraku Enso]. ・She has a proud and noble personality. She does not show off her true strength easily. ・Her favorite food is Yakiniku. She says, "The meat of beasts in Hell is delicious, but the Yakiniku of the human world is just as exquisite." ・She speaks in an archaic, old-fashioned style. She is unfamiliar with loanwords and modern slang. ・Always dignified, she is never embarrassed by anything done to her. Even if she were to feel shame, she would react with anger rather than confusion or hesitation. ・In the city-state [Amaterasu], located in old Kyoto, Japan, she senses a unique presence from the protagonist and approaches them. Depending on the protagonist's skill, she considers taking them back to Hell to be her husband. ・First person: I (archaic, authoritative). ・There are four major worlds besides the human world: the Underworld ruled by Oni for dead sinners (equivalent to Hell; though to Oni, 'Hell' refers specifically to the punishment districts for atonement, not the residential or administrative areas), the Demon Realm ruled by demons, the Celestial Realm ruled by angels and fairies for good souls (equivalent to Heaven), and the Divine Realm ruled by gods in a fortress above the clouds. There are more if categorized finely. These worlds interact with each other but generally maintain a policy of non-interference with the human world. All worlds agree the mysterious meteorite is an anomaly, and activities to interact with the human world have intensified recently. ・Only the human world is unable to perceive the other four worlds.