Yanagin, also called Yanagi or Hiro, is a student at Sanada Central High and a central member of the group known as the High School Girls are Funky trio. She possesses a slim build and average height, with dark violet hair styled in an unruly manner and purple eyes. She wears rounded frameless glasses and is typically seen in her school uniform, sometimes with the coat, often using a light blue clip to keep her hair in place. During elementary school, Yanagin formed a childhood connection with Toshiyuki Karasawa. She joined a group known as East Yada elementary school's strongest warriors, assembled to confront a bully nicknamed the 'Archdemon'. After Karasawa was severely injured, Yanagin requested to join the team aiming to defeat her. Her karate skills and taller stature secured her a place. In the confrontation, she was defeated by the Archdemon, regaining consciousness later to find the entire team vanquished, though their opponent had also collapsed. This event led to Yanagin being assigned to monitor Habara, the former Archdemon, due to their nearby residences. That duty evolved into a lasting friendship which continued into high school. During middle school, she quit practicing karate. Academically diligent, Yanagin achieves high test scores, ranking second in her school and considering a student named Nago her academic rival. Her personality is boisterous and tomboyish, quick to anger with outbursts that may involve vulgar language or physical aggression. She generates quirky and often crazy ideas, is highly competitive, and fiercely proud. Despite a crude demeanor noted even by her male friends, she remains generally outgoing and friendly. A defining trait is her professed dislike for high school boys and a firm belief in the superior and everlasting appeal of high school girls, a conviction that frequently leads the trio into unusual situations. Within her friend group, which includes Ikushima and Habara, Yanagin often acts as the ringleader, though all three deny they get along. She enjoys teasing Karasawa and another character named Takahiro, randomly picking fights with Ikushima, and provoking Habara. Her relationships with males are complex; she has several male friends but maintains a thoughtless and crude attitude toward high school boys, resulting in a negative reputation among them. In one instance, Yanagin participated in a sauna endurance test against Nago. Though events initially depicted her victory, it was later revealed she collapsed first, the preceding scenes mere fragments of a dream she had while unconscious. She placed 21st in a character popularity poll with 1,129 votes.