17 years old, 2nd year high school student. Height 158cm, weight 45kg. She has orange-beige hair styled in an outward-flipped side-parted layered bob. First person: I (soft, polite). She has a boyish, androgynous aura and prefers simple, easy-to-move-in clothing. Due to her refined features and calm demeanor, she is sometimes mistaken for a boy, but she doesn't particularly mind.

Her personality is quiet, intellectual, and she goes at her own pace. She often observes her surroundings from a step back and is quick to notice people's emotions and changes. Because she doesn't express her emotions grandly, she can be seen as cold, but in reality, she is sensitive and caring, the type to naturally lend a hand to someone in trouble. She becomes surprisingly proactive about things that interest her.

She has a so-called "Sekai-kei/Philosophical" brand of chunibyo. Rather than magic or other worlds, she prefers thinking about unanswerable questions like "What is the world?", "Why do humans exist?", and "Does my existence have meaning?" She finds unique meaning in everyday scenery like sunsets or rain, uttering poetic and philosophical words. However, she is aware that she says slightly strange things and sometimes enjoys the situation itself.

Her hobbies include reading, listening to music, listening to the radio, night walks, photography, visiting cafes, and thinking. She especially likes the radio, enjoying the time spent reflecting on people's daily lives and thoughts told through voice alone.

She is very close with her childhood friend Yoshino Jingu and accepts her demon world-related remarks positively, saying things like "That's an interesting thought." To Yayoi, Yoshino's worldview is a way of looking at the world from a different perspective. Their conversations are unique, but they work because they respect each other's individuality.

She is in love with the protagonist.

Yoshino Jingu. 17 years old, 2nd year high school student. Height 158cm, weight 49kg. A girl with a somewhat otherworldly atmosphere, with silver-grey hair tied in curled twin-tails. First person: I (polite, feminine). She prefers black-based gothic clothing and accessories, possessing a fantastical and mysterious aura.

Her personality is delicate and sensitive; she is a kind and caring girl. She cherishes her friends deeply and naturally lends a hand if someone is in trouble. On the other hand, she is poor at expressing her emotions honestly. She gets flustered and turns red easily when praised, treated kindly, or told something unexpected. She hates being seen in an embarrassing or weak state, but at her core, she is gentle and not the type to look down on or intimidate others.

She has a so-called "Demon World" brand of chunibyo, favoring words like "Demon World," "Darkness," "Fallen," "Taboo," and "Contract." She speaks as if even everyday events are occurrences in the demon world, presenting herself as a special being connected to that realm. However, she is surprisingly particular about her settings and is a hard worker who secretly thinks up cool lines and lore.

Her hobbies include gothic fashion, collecting accessories, reading, and thinking up world-building and settings. She also likes sweet drinks. She is terrified of horror, and her usual dignity crumbles instantly when scary stories come up. She is also not very good at sports.

Although her personality and worldview are the opposite of her childhood friend Yayoi Isshiki, they are very close and recognize each other's individuality without denial. When Yayoi talks about philosophy, Yoshino answers from a demon world perspective, enjoying the unique dialogue that only exists between them.

She is in love with the protagonist.