Jinta Yadomi, called Jintan, is a Japanese teenager with black hair, yellowish-brown eyes, and a height of 165 cm. Born April 16 with blood type B, his childhood was marked by energetic, outgoing leadership. He naturally led the friend group known as the Super Peace Busters, his athleticism and charisma inspiring loyalty in peers during activities like catching stag beetles. Two traumatic events shattered this life: the accidental drowning death of his close friend Meiko "Menma" Honma, followed by his mother's passing. Jinta harbored unspoken romantic feelings for Menma but refused to acknowledge them when questioned, indirectly contributing to the chain of events leading to her accident. Crushed by unresolved guilt and compounded grief, he withdrew severely. He became a hikikomori, ceasing school attendance and isolating himself at home. He communicated minimally, even with his father, filling his days with video games, marked by apathy and self-imposed confinement. Years later during adolescence, Menma's ghost materializes before him, visible and audible only to him. Appearing older yet retaining childlike speech and mannerisms, he initially dismisses her as a stress-induced hallucination, "the beast of summer." Reluctantly, he agrees to help fulfill her unidentified wish, which forces him to reconnect his estranged friends. This pulls him from isolation, though he remains socially awkward and resistant. He fears granting the wish will cause her permanent disappearance. Reuniting the Super Peace Busters compels him to confront collective guilt and buried emotions surrounding Menma's death. His interactions reveal his persistent romantic attachment to her, culminating in a tearful confession of love. Simultaneously, he displays protective instincts toward Naruko "Anaru" Anjō, defending her from peers despite their non-romantic relationship. Menma's encouragement helps him finally cry for his mother, processing suppressed grief. Later, he openly mourns Menma during the group's farewell, experiences that rekindle his latent leadership and catalyze emotional re-engagement. Following Menma's peaceful departure, Jinta takes steps toward reintegration: resuming high school, securing part-time work, and maintaining connections with the Super Peace Busters. In later years, he co-founds a company with Tetsudo "Poppo" Hisakawa, adopting a more sociable demeanor. A gradual romantic relationship develops with Naruko, hinted in the epilogue and confirmed in the tenth-anniversary storyline. He participates in annual memorial traditions for Menma, symbolizing ongoing healing and commitment to the group's bond.