Asahi Azumane honed his powerful spikes at Seikoudai Junior High, earning recognition for wielding the force of a high school player. He brought this strength to Karasuno High School's volleyball team, quickly becoming their ace. However, a devastating loss during his second year, where Date Tech High blocked every one of his spikes, plunged him into crushing self-doubt. Blaming himself for the defeat, Asahi quit the team. His departure sparked a fierce confrontation with teammate Yu Nishinoya, who vehemently opposed Asahi giving up. Their argument escalated when Asahi accidentally broke a broom; the next day, Nishinoya broke a vase while confronting him again, resulting in Nishinoya's suspension. This chain of events cemented Asahi's departure from volleyball. A month later, persistent encouragement from first-years Shoyo Hinata and Tobio Kageyama, coupled with Asahi's own lingering passion, convinced him to return. He rediscovered his resolve during a Neighborhood Association scrimmage, vowing to keep spiking despite blocks. Scoring a decisive point reclaimed his identity as Karasuno's ace, with Nishinoya promising support against future blocks and reinforcing their partnership. Standing 184.7 cm tall, Asahi possesses long dark brown hair typically tied in a bun and sports short chin scruff, creating an intimidating appearance often mistaken for adulthood. This led to misunderstandings and unfair rumors, including accusations of forcing students to fight or selling drugs. Post-graduation, he wears his hair down with red-framed glasses. Despite his imposing look, he is gentle, soft-spoken, and prone to anxiety, earning him the "glass heart" descriptor for his sensitivity to criticism. He initially struggled under the burden of ace expectations but gradually embraced the role, vowing never to relinquish it. Key matches marked his development. He overcame past trauma by breaking through Date Tech's "Iron Wall" at match point in an Interhigh rematch. During training camps, he supported insecure teammates like Kei Tsukishima, drawing from his own experiences. At national tournaments, he delivered clutch performances, including powerful serves against Shiratorizawa and match-deciding spikes against Inarizaki, solidifying his reliability. After graduating in 2013, Asahi pursued a career as an apparel designer in Tokyo. He reunited with Nishinoya in 2021 to attend the Tokyo Olympics and travel to Egypt, maintaining their friendship. As of 2018, he was 23 years old, making him 30 by May 2025.