Maki Okonogi is a student at a special school located in the mountains, an institution that serves demi-humans who aspire to become fully human. She is a descendant of the oni, a type of creature from Japanese folklore. Her appearance is marked by several distinctive traits, including her purple hair, which she wears in braids, and her red eyes, which are noted for being heterochromatic, meaning they are of two different colors. She also has blunt bangs and small horns that signify her oni heritage, often seen wearing her school uniform or a hoodie.

In terms of personality, Maki is known for being carefree and laid-back in her nature. She frequently makes jokes and speaks in an offhanded or casual manner, bringing a light-hearted presence to her class. This easygoing attitude is a core part of her character, and she does not appear to be weighed down by her identity as a demi-human. Her primary motivation for wanting to become a human is rooted in a personal principle; she has stated that she chose this path because she does not want to lie. This reasoning suggests a value for honesty and perhaps a belief that humanity represents a state of being free from pretense or falsehood.

Within the story, Maki is one of the students under the charge of the protagonist, Rei Hitoma, a self-professed misanthrope who has taken up the teaching position. She therefore plays the role of a student whose development and interactions serve as a central part of the narrative. Her key relationships are primarily with her classmates, who include other demi-humans such as a mermaid, a werewolf, and a dragon, as well as with her teacher. Her birthday is February 3rd.

Information regarding her specific development throughout the series or any notable abilities beyond those inherent to her oni lineage is not available.