Haruomi Date is a second-year student and a key player for the Saitama Futaba badminton team, a school renowned as a five-time inter-high champion. He stands out among his strong teammates as a particularly formidable opponent, with Coach Ebihara noting his potential as a player to closely watch in tournaments. Date's abilities are significant, as he is shown defeating an opponent who competes at the national level.

His personality is notably provocative and arrogant. He acts in a deliberately obnoxious manner that tends to alienate those around him. This demeanor is rooted in a deep-seated rivalry and personal issue with another player. Date specifically harbors a strong grievance against Kento, the protagonist, which stems from his inability to comprehend why a talented player like Kento would choose to join a team he considers weak. This incomprehension fuels his confrontational attitude and his specific beef with Kento. His role in the story is that of a rival, serving as a significant obstacle whose presence forces the main characters to acknowledge the high level of competition they must face. Despite his impressive skills, his motivations are largely driven by this personal judgment of Kento's choice, making his character central to the competitive tensions on the court.