|Aliases|| Crimson Scholar|
|Hair color||Dark Red|
This Demon King (魔王; Maō), also translated as Demon Queen or Maou, is the main female protagonist and the 43rd Demon King, the supreme ruler of the Demon Realm. Her title is "Ruby Eyes" named after her ruby eyes. After teaming up with the Hero, she disguises herself as a human noblewoman known as the Crimson Scholar (紅の学士; Kurenai no Gakushi), and shares her vast knowledge on such topics as economics and farming.
She comes from the Library Clan, a clan of demons that prioritize knowledge. They reside in a hidden dimension called the Exterior Library, which contains a vast archive of knowledge from various times and alternate universes. Instead of a desire to conquer the human realm, she instead wants to see the "other side of the hill," a world where both the humans and the demons were freed from war.
The Demon King is a woman of average height. She has (detachable) horns and long, flowing red hair reaching some way down past her shoulders. Similar to her hair, she has deep, ruby colored eyes that are reflected in her Demon King name, Ruby Eyes. Even though she has the appearance of a young woman, she is in fact over a hundred years old.
She wears a long, red robe that reaches down to her feet, the robe has an open front, revealing her ample cleavage. This robe has a feathery collar, similar to a boa; and a red diamond pattern running along it's black sleeves. The front of the dress features a large orange stripe framed by smaller black stripes and she has a small bow on the front of her dress below her breasts.
The Demon King is generally easy-going and very cheerful and relaxed. So much so, she greeted the Hero who'd come to kill her, with a simple "Hello!"; stopping him mid-swing and startling him.
She also seems to have less modesty than most, as she had no problem nearly fully exposing her breasts to the hero to show him her "Demon Mark" to prove that she is the "Demon King". At the same time, she dislikes wearing revealing clothing (those were Senior Maid's choices in fashion) and would rather don casual, modest attire. Though an imposing and intelligent woman, she has shown a bit of a childish and comedic side.
As a member of the Library Clan, the Demon King has access to the Exterior Library, where she lived for most of her life. At some point in time before Hero was born, she met and saved Senior Maid, saving the latter from being a "bug." After that, Senior Maid has faithfully devoted herself to her mistress.
When Hero was a toddler, she had already risen to the position of Demon Lord after overthrowing the previous Demon Lord in a coup. However, not too long after, even after she resealed the Gate between the human and demon world, the Second Holy Crusade broke through and conquered Gateway City.
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 once 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.
Reclaiming Aurora IslandEdit
Attack on the Southern UnionEdit
Third Holy Key ExpeditionEdit
Unlike every other Demon King, she is only on par with a strong human. Hero states that she is, at best, on the Lone Winter King's level at fighting. This comes back to bite her during the Kurultai, first because some of the major clan leaders refuse to acknowledge her as Demon King due to her weakness, and second when she is hit by a poisoned arrow and is barely strong enough to survive the assassination attempt. Her real strength, however, lies in her broad range of knowledge and strategic prowess.
As a member of the Library Clan, she is also capable of seeing events in the far past and even the far future. It was through this ability that she learned how to construct the rifle, among many of her other achievements.
Under the Corruption of Past Demon Kings Edit
When possessed by the spirits of the past Demon Kings, who lust for war and bloodshed, she displays abilities that they have possessed, making her a much more potent combatant than usual.
Shouting: The Demon King possesses some kind of shouting that allows her to push back her foes with her voice. Magical foes, like the Senior Maid's ghosts, are dispersed and non-magical targets are pushed back.
Summoning: The Demon King can summon any weapon to help her fight. She has summoned a demon sword and a large demon scythe to help her fight.
Swordsmanship: The Demon King possesses swordsmanship greater than what a regular demon would know of. She was able to out skill her Senior Maid by cutting off her maid's arm.
The Demon King has always been in love with the Hero and anticipated their meeting from the moment of his birth. As he grew up, she continued observing his growth.
Since both are having a crush for the Hero they consider each other as love rivals and try to obtain the Hero's attention and hoping for him to choose them. Despite their love rivalry, the two are on good terms with each other and respect each other's skills and knowledge. They do consider themselves as friends throughout the plot, and trust one another.
Because of Demon King's weakness in combat, Duke Silver Tiger initially refuses to accept her as the supreme ruler of the Demon Realm and fights with her whenever he can. However, as an honorable warrior, he agrees to at least hear her out after the "Dark Knight" (Hero in disguise) defeated all of his best warriors in combat. When the Blue Demon Clan calls to overthrow her, though, Duke Silver Tiger readily opposes the Demon King.
Nevertheless, after Archer exposes the Blue Demons' assassin who had supposedly killed the Demon King, Duke Silver Tiger is horrified to discover that the assassin was one of the Beast Fang Tribe. When the true Demon King reveals herself to be alive and orders the Seal King's capture, Duke Silver Tiger sides with her, enraged by the dishonor of the Blue Demon Tribe. Afterwards, he apologizes to her for the assassin, and begs her to have compassion on his Tribe. She, however, has no ill will against the Beast Fang Tribe and believed that they were innocent all along.
As a result, he promises to repay her generosity by becoming her shield, claiming that this debt would not be repaid until the Beast Fangs had shielded her life three times. This debt is what ultimately kills him, as he dies defending her from the Lily Knights' bullets. Between the Kurultai and his death, the two are on much better terms with each other, with Demon King taking his advice on how to react to the Blue Demons' invasion of the Human Realm.
- "Hello, Hello Hero." —To Hero
- "Do evil, get caught, then claim demons were brainwashing you. A common way that human politicians evade responsibility." —To Hero
- She thinks herself as unattractive due to her flabby underarm fat.
- She calls her breasts unnecessary flesh. Her Senior Maid also agrees with her.