Yui Kurata

14 years old, height: 147cm (Yui in the "Dream World" is 154cm), measurements: B 84/W 55/H 83 (Yui in the "Dream World" is B 87/W 59/H 88 with a G cup). One of the "Trinity Seven." Her specialty magic is Heavy Choral Magic (Arc Symphony). Her "Archive" is Greed (Avaritia), and her "Theme" is Friendship (Amicitia). The magic book she possesses is "Aleister's Grimoire." Her secret technique is Dream Limit (A Maimon). She is commonly known as the "Cardinal Demon Lord."

A young mage girl who spent a long time in the Dream World. She possesses cardinal-class magical power, second only to the headmaster, and was put to sleep in the underground labyrinth to suppress it. Her appearance differs between the real world and the "Dream World," with the former being petite but well-developed, and the latter being taller and more mature. According to Arin, Yui in the Dream World is her "ideal form." Like Arin, she shows no shyness, even taking Arata's hand to touch her chest. She is skilled at playing the violin. Mages usually use aliases, but in Yui's case, she doesn't even know her real name.

Before the story begins, she was conducting research by simply sleeping in the depths of the labyrinth, intending to eventually erode and destroy the real world with her dreams and the monsters within them. After meeting Levi through the headmaster's guidance, she became friends with her as they shared a research direction of "not needing others at all, but therefore constantly seeking the existence of others."

When Arata's magic was sent into a rampage by Arin, Yui saved him by pulling him into her "Dream World" and gave him a hint to control the "Collapse Phenomenon" he caused. However, by allowing Arata, a Demon Lord candidate, into the Dream World, Yui's own magic was later affected and went out of control, causing a "Collapse Phenomenon" that put students with low magic power in the academy to sleep. She was later rescued by Arata and the other Trinity Seven, and developed feelings for him. Since then, she has shown the most straightforward affection among the female characters, actively hugging Arata and kissing him on the cheek, even declaring to Arin that "Yui is fine being a mistress." After the incident was resolved, she began living a normal school life, as Arata's magic nullified the magic overflowing from her.

A genius among the Trinity Seven, her inexhaustible magic power is stabilized by constantly creating the Dream World. Additionally, if she forms a domain where she can fully exert her power through a barrier, she can transform into her mature appearance even in the real world. She has a high aptitude for controlling and forming space through sound, and by combining it with her "Phantom Cross Eyes," which lure opponents into the boundary between dreams and reality, she exhibits immense power.

In the Divine Comedy Gate arc, her lack of desire gathers an extraordinary amount of greedy magic power, which becomes strong enough to instantly defeat two of the Twelve Demon Generals. Later, she imprisons the vice-leader of the Twelve Demon Generals, Albalicia, within her dream using a limited edition of the Ultimate Magic Law, allowing her to use Albalicia's magic power and summon her with a temporary body into the real world at will. During this time, it is revealed that there is a "sleeping Yui Kurata" nested within her dream, and she confesses to having an overwhelming sense that "the whole world might be a dream I am seeing." She tells Albalicia that she cherishes Arata because, in a world where she can't distinguish between dreams and reality, he is the only one she believes to be "real."