Hayato Matsuura works part-time at a diving shop, sporting a prominent hair antenna and assuming a steadfast supportive role. His interactions with the protagonist blend approachable friendliness with a subtle flirtatious streak, distinguishing him from coworkers whose motives remain less defined. Primarily seen fostering workplace camaraderie, he provides consistent encouragement through casual exchanges and shared professional tasks. His narrative contributions center on collaborative moments, with no elaboration on personal history or external arcs beyond his role in the central story’s social dynamics.