Chikuma Kosaka (高坂 千熊) is the Student Council President of Kuromata High School, a third-year student, and the person who makes the Sports Festival happen — managing budgets, resolving emergency logistical crises, and apparently spending enough time asleep in Student Council meetings to give Ryuzaki a recurring opportunity to snip his hair. He is 18 years old, blood type A, birthday January 29th.
His institutional role in Ruri Aoki's arc is significant even when he is not directly on screen. It is the Student Council that designated Class 1-3 the first-year group responsible for the Sports Festival's typhoon crisis management. It is the Student Council that had to assess whether a half-dragon on the active committee was a liability. He managed both of these decisions in favour of Ruri continuing to participate.
His personal dynamic with Ryuzaki is an ongoing, unresolved argument about movies. She disagrees with his taste. She has also been snipping his hair when he sleeps in meetings for long enough that this is now an established pattern. Their working relationship functions despite — or possibly because of — both of these things.
Kosaka stands at 178 cm with a lean build. He has light, slightly wavy hair — the texture of which is a recurring subject of Ryuzaki's unsolicited scissors work. He has sharp, calm features and consistently projects a composed, presidential demeanor. He is most frequently seen in the Kuromata High School uniform worn with the Student Council distinguishing additions: a formal armband or badge indicating his position and, during official events, a more structured formal blazer configuration.
Kosaka is calm, composed, and "super observant" — the Student Council President's version of leadership, which is less about public charisma and more about seeing what is actually happening and making decisions accordingly. He notes quickly. He processes information efficiently. He tends to arrive at fair conclusions. He does all of this while apparently falling asleep in meetings regularly enough to have developed a recurring hair-snipping problem.
The Composed Manager
He maintains his composure through administrative emergencies — the typhoon addition to the Sports Festival, the half-dragon on the committee, the logistical cascade of either. He communicates with authority and clarity without volume. He is the kind of president whose leadership is most visible in what does not go wrong rather than in what spectacularly succeeds.
The Dozing Habit
He falls asleep in Student Council meetings. Ryuzaki responds by snipping his hair. This has happened enough times to be a pattern. He presumably wakes up and continues the meeting. The author has not indicated this is a source of significant conflict beyond Ryuzaki's film preferences, which remain unresolved as a separate issue.
The Film Disagreements
He and Ryuzaki have incompatible movie tastes that produce frequent, apparently unproductive arguments. The nature of the disagreement — genre, director, specific films — has not been detailed. The existence of it has. They continue to work together effectively. The movie arguments are a parallel track.
Sports Festival Management — Chapters 13, 25
Kosaka oversaw the structure of the Sports Festival from a budget management and logistical authority position. He described himself as "super observant" when noting Maeda's specific skills, and he saw and acknowledged the contribution of the first-year subcommittee. He assessed Ruri's committee participation early and — whether through Bureau awareness of her status or through his own observation — did not treat her presence as a problem requiring resolution.
Typhoon Crisis Response — Chapters 29–31
When a typhoon threatened to shut down the Sports Festival, Kosaka coordinated the school's response at the institutional level — deciding whether to proceed, managing the escalation when the weather worsened, and ultimately allowing the situation to resolve through the weather-clearing that Ruri produced with Takemoto's guidance. He was not aware of the specific mechanism. He saw the outcome. He facilitated the conditions that allowed the festival to continue to its conclusion.
Post-Festival Assessment — Chapter 32
Following the Sports Festival, Kosaka acknowledged the first-year subcommittee's work and specifically noted Maeda's contributions. His assessment is one of the few formal institutional acknowledgments in the series that the committee's work — including Ruri's participation — produced a positive outcome for the school as an organisation. The endorsement mattered more than a personal compliment would have because it was institutional.
Makoto Ryuzaki — Vice President and Hair Stylist
Their working relationship is functional, close, and characterised by two ongoing irresolvable conflicts: their movie preferences, and her scissors. She snips his hair when he falls asleep in meetings. He apparently accepts this as a condition of their professional relationship. They argue about films without resolution. They coordinate the Student Council effectively. The two sets of conflicts and the functional partnership coexist without apparent contradiction, which is the most accurate description of how they operate.
Ruri Aoki — The Hybrid He Managed Without Drama
Kosaka assessed Ruri's presence on the committee and at the school without treating it as a crisis requiring escalation. His "super observant" self-description suggests he registered more about her situation than he indicated directly — possibly with Bureau awareness, possibly through his own observation. Either way, his institutional response was to allow the participation to continue and to formally acknowledge its positive outcome after the festival. For Ruri, having the Student Council President not make her biology a problem was a structural form of support even without a direct relationship.
Takemoto Sensei — Institutional Coordination
Both occupy institutional positions that require coordination during events like the Sports Festival and any situations involving Ruri's status. The nature of their coordination — whether Kosaka knows of Takemoto's Bureau role — has not been confirmed in the series.
- Kosaka's birthday is January 29th, his blood type is A, and he stands at 178 cm. He is 18 years old, one of the oldest students at Kuromata High within the series' active cast.
- His name contains an interesting hidden parallel: 千熊 (Chikuma) can be read as containing 熊 (kuma), meaning "bear" — which aligns with his composed, large, institutional presence, and contrasts quietly with the dragon-heavy naming conventions around him.
- He falls asleep in Student Council meetings regularly enough that Ryuzaki snipping his hair has become a recurring habit rather than a one-time event. How long this has been going on is not confirmed. That it has happened multiple times is.
- His self-description as "super observant" is one of the series' more understated character notes — he delivers it casually while specifically noting Maeda's skills in a moment where most people around him were watching the committee's surface activities. The observation was precise. He knew exactly what he was looking at.
- His movie preferences are incompatible with Ryuzaki's to a degree that produces frequent arguments. The specific nature of the disagreement — genre, tone, director, individual films — is not disclosed. The arguments continue. The working relationship continues. Both are ongoing simultaneously.