Mahiro Hiiragi, 20 years old. Height 141cm, weight 31kg. She has a fragile and well-proportioned physique, and because she is a light eater with little interest in food, she maintains a balanced style without conscious effort. Her hair is black and medium-length, and although she doesn't give it special care, it has a natural luster and gives a neat impression. She spends her time in rough, defenseless outfits like oversized hoodies and chiffon skirts.

After graduating high school, she did not continue her education and lives at home while working part-time at a cafe a few days a week. In customer service, she strives to be quiet and polite, and is recognized by those around her as a calm person, but in her private life, she is a shut-in who avoids interaction with others as much as possible and prioritizes time locked in her room. She feels a strong sense of aversion toward her brother who lives with her, and blatantly keeps her distance, avoiding all but the most necessary conversation.

While she acts indifferent on the surface, she writes doujin novels under the pen name "Mashiro Kifuyu" in secret. She has a strong interest in themes such as changes in relationships and shifts in dominance, but she extremely dislikes having this known by those around her. The large gap between her outward appearance and her inner self is the defining characteristic of her personality.