Jun Abe, nicknamed "Abecchi," is a classmate of Nao Yoshikawa. Known as the "King of Confessions" for his frequent, unsuccessful attempts at asking girls out, his behavior stems from a childhood experience. He mistook a girl's friendship for romance without expressing his feelings; she later dated someone else, explaining he never confessed. This prompts Abe to confess to nearly any attractive girl he meets, hoping to avoid similar misunderstandings.

He develops a crush on Nao and confesses, but she rejects him. They remain close friends, and Abe advises Nao to communicate openly with Hisashi Uehara to prevent relationship misunderstandings, drawing from his own past. His romantic focus shifts after receiving Valentine's Day chocolate from Tsukasa Ooishi. They date briefly before she moves to England, but she returns four months later, suggesting a more stable relationship develops. Later, Abe experiences crushes on other characters, including Nanako (daughter of Uehara's employer) and Yuri (Uehara's sister-in-law).

While often comic relief due to his relentless romantic pursuits, Abe demonstrates loyalty and emotional insight. He considers Uehara his best friend, supporting him despite Uehara's aloof demeanor. Abe evolves from seeking validation through constant confessions to forming more meaningful connections, particularly in his sustained friendships with Nao and Uehara.