Kiyoshi Fujino is portrayed as the most level-headed and composed among the five male students at Hachimitsu Academy. Known for his calm demeanor in high-pressure situations, Kiyoshi frequently assumes the role of the group’s rational thinker, often keeping his impulses in check compared to his more eccentric peers. His character design and internal narration reflect his role as the “everyman” of the group, providing much of the story’s grounded perspective.

While not without flaws, Kiyoshi demonstrates notable self-restraint, especially in situations charged with sexual tension. He lacks the overt perversion characteristic of the other boys, though he is not above engaging in morally questionable antics such as cross-dressing or staging elaborate schemes to achieve his goals. Despite these occasional lapses, his actions are usually driven by sincere motives, particularly his affection for Chiyo Kurihara.

Kiyoshi’s feelings for Chiyo grow into a deep, romantic devotion that motivates much of his behavior throughout the series. His efforts to win her affection include organizing daring escapes, sacrificing personal dignity, and enduring punishment all to remain close to her and nurture their relationship. However, Kiyoshi is not immune to selfishness. At times, he can be unaware of how his actions affect others, such as when he intended to use shared funds for a personal purchase. Still, he often acts out of loyalty to his friends, as seen when he risked punishment during a breakout attempt to help Gakuto retrieve a prized figurine. Though driven by personal emotions, Kiyoshi’s integrity and sense of loyalty often shine through.

Kiyoshi Fujino is a tall and reasonably attractive young man with a lean build, dark blue hair, and sharp black eyes. At the start of the series, his physique is fairly slim, but his time spent in the school’s Prison Block leads to a noticeable increase in muscle tone due to the physical labor and harsh conditions.

While incarcerated, Kiyoshi typically wears the standard male prison uniform, a long-sleeved, white and blue striped shirt paired with matching striped trousers. Notably, during his second stint in the Prison Block, he is briefly seen wearing only boxers, having lent his prison clothes to Chiyo Kurihara in a moment of selflessness (and mischief).

Chiyo Kurihara
From the beginning of the series, Kiyoshi harbors a romantic interest in Chiyo Kurihara, the younger sister of the Underground Student Council president. Their connection begins with a seemingly innocent conversation sparked by a sumo-themed eraser gifted to Kiyoshi by his mother, an item Chiyo immediately recognized and appreciated. Although Kiyoshi is not a genuine fan of sumo wrestling, he pretends to be one to impress her and even promises to watch a match with her and share a meal afterward. This promise becomes a major motivation behind his elaborate attempts to escape from the school’s Prison Block.

Kiyoshi’s behavior notably shifts when he is around Chiyo, often becoming shy and reserved compared to his usual attitude. This contrast is especially apparent to his friends, who remark in the OVA that Kiyoshi appeared colder and more serious in prison but becomes noticeably awkward and flustered in Chiyo’s presence. He often fantasizes about her something he does not do with any other girl in the series highlighting the uniqueness of his affection for her.

Hana Midorikawa
Initially, Kiyoshi views Hana Midorikawa, the secretary of the Underground Student Council, as another sadistic authority figure overseeing his punishment. However, their dynamic shifts dramatically after an embarrassing incident where Hana accidentally exposes herself while urinating, with Kiyoshi unintentionally witnessing the act. Deeply humiliated, Hana becomes obsessed with exacting revenge on him, which begins a bizarre series of encounters laced with tension, awkward intimacy, and escalating humiliation.

Throughout the series, Hana orchestrates increasingly perverse scenarios in an effort to settle the score, though her plans frequently backfire, leaving both parties humiliated. Despite her initial disgust and antagonism, Hana becomes emotionally entangled in her interactions with Kiyoshi. Her obsession is driven not only by vengeance but also by a deeper confusion regarding her own feelings especially as she refuses to back down, claiming she always sees things through to the end, even if it means pushing the boundaries of decency.

Mari Kurihara
Kiyoshi’s relationship with Mari Kurihara, Chiyo’s older sister and the president of the Underground Student Council, begins as one of opposition. Mari is one of the key figures responsible for the boys’ incarceration. However, over time, their interactions evolve into something more complex. Following Mari’s own imprisonment, the two develop an unusual rapport marked by moments of mutual understanding and unspoken complicity, which occasionally stirs jealousy in Chiyo and intrigue in Kate, Mari’s rival.

Despite the often absurd and inappropriate circumstances that bring them closer such as moments of accidental physical contact—Kiyoshi shows a surprising degree of comfort around Mari. Unlike with Chiyo, he exhibits boldness in speaking openly, initiating physical gestures, or even crossing boundaries (albeit usually punished with violent retaliation). Their relationship becomes one of awkward trust, where Kiyoshi, despite the tension, views Mari as a respected friend and even imagines her as a future sister-in-law, going so far as to ask for her blessing before confessing his feelings to Chiyo.

The given name Kiyoshi (清志) is composed of the kanji 清 (kiyo), meaning “clear,” “pure,” or “clean,” and 志 (shi), which signifies “will” or “purpose.” Together, the name can be interpreted as “pure will” or “clear intention,” reflecting Kiyoshi’s often sincere and determined nature throughout the series.

His surname, Fujino (藤野), combines 藤 (fuji), meaning “wisteria,” a flower often associated with grace and endurance, and 野 (no), meaning “field” or “wilderness.” The name could evoke imagery of a wild field of wisteria, possibly symbolizing Kiyoshi’s balance between gentleness and resilience in the face of adversity.