The female lead protagonist. The 43rd ruler of the Demon World and the youngest to rule by demon standards, she is a powerful sorceress but has no experience in battle. Wise and smart, her vast knowledge comes from the "Exterior Library", a hidden dimension where knowledge of the past and future is kept and where her clan lived. Despite her knowledge, she is considered incompetent by the warmongering demon clans. Seeing what would happen to the war if it didn't end without the problems that it cause fixed, she awaited the arrival of the Hero so she could ask for his help to end war the right way. After finally getting him as her ally, she and the Hero travel to the Human world where she takes the identity of the Crimson Scholar, a human noble who has come to help the lower classes.
The Demon King is seen pondering, completely oblivious of the Hero charging towards her, intending to kill her. Even with the Hero charging towards her, she remained perfectly calm, and simply turns around; greeting him with a simple "Hello there", startling the Hero mid-swing. After she shows the Hero her "Demon Mark" as proof of being who she is. She explains to the Hero that because of this war, the people in faraway nations, who are helping the war effort, are only able to have their luxuries because of the war. In her room, she gives the Hero the Demon Lamp to hold, and after she explains what is really going on in his memory, they return to her room, where she also shows him where she would like to see. After this, she one again tells him that he will be hers, to which he replies that she is his. She accidentally touches the Demon Lamp again, where a memory of her hugging a bag with the Hero painted on it. After the memory dismisses, she tells the Hero to forget what he has seen. She then shocks the Hero again by taking her horns off, before they leave to go to the hill.