Tetsudou Hisakawa, universally known by his childhood nickname Poppo, is a core member of the close-knit group the Super Peace Busters. As a child, he sported a shaved head and a smaller frame, typically dressed in a blue hoodie and track pants. He idolized Jinta "Jintan" Yadomi, frequently expressing awe at his actions and feeling profoundly grateful for his inclusion in the group, viewing himself as an awkward child. Poppo directly witnessed Meiko "Menma" Honma's fatal accident, an event that burdened him with persistent guilt over his perceived failure to save her, a feeling he masked behind a cheerful demeanor. Following Menma's death, Poppo dropped out of high school and traveled the world, funding his journeys through various part-time jobs, including construction work. When not abroad, he resided in the group's abandoned childhood secret base. Despite his nomadic life, he maintained a worldly and mellow attitude. He became the first among the friends to believe Jinta's claim of seeing Menma's ghost and the first to commit directly to fulfilling her wish so she could move on. He frequently acted as a peacemaker during the group's conflicts, actively driving their reunion and encouraging them to support Menma's unresolved desire. Poppo carried a pouch necklace holding flowers that bloomed near the site of Menma's death, a silent tribute representing his lingering remorse. His guilt manifested in vivid, recurring memories of her drifting away during the accident, a pain he initially avoided confronting through his travels and outwardly carefree attitude. However, as the group united to help Menma, Poppo openly confessed his long-held guilt during an emotional confrontation, marking a crucial step in his personal healing. After Menma found peace, Poppo achieved significant personal growth. He co-founded an import business with Jinta, establishing professional stability. By the group's reunion one year later, depicted in the sequel film, he was no longer tormented by his past and had begun processing his emotions more healthily. A decade after these events, he became the only member of the Super Peace Busters to marry and have children, indicating a settled and fulfilling family life alongside his continued friendship with Jinta. This evolution from a restless traveler burdened by hidden trauma to a grounded family man and entrepreneur completes his journey toward acceptance and stability. His name, meaning "iron path," reflects his eventual resilience, while his surname "Hisakawa," translating to "long time river," symbolizes the enduring flow of his life experiences and relationships.