TV-Series
Description
Daiichi Yamura is a middle school student and one of the children chosen to pilot the giant robot Zearth. He is the eldest brother in a family of four siblings, responsible for caring for his three younger siblings named Yoshi, Futaba, and Santa. Their mother passed away when they were young, and their father abandoned the family for unknown reasons approximately three years prior to the story's events. To compensate for his brother's disappearance, Daiichi's paternal uncle rented a home for the four children to live in and covered all their living expenses.

Despite the support from his uncle, Daiichi demonstrates a powerful sense of independence and responsibility. He chooses to live separately from his uncle with his siblings specifically so that his father would still have a place to return to if he ever decided to come home. To contribute to the household, Daiichi works multiple jobs, including delivering mail and newspapers, as well as working for his uncle's landscaping business on his days off. This work ethic defines his character, as he is described as a hard-working and diligent boy. His exterior can be gruff and no-nonsense, but this masks a deeply caring and responsible nature.

When the group of children first becomes involved with Zearth, Daiichi is the first to express doubt about their situation and the first to attempt to leave the "game" before they learn the full, deadly truth of their contract. Among the other pilots, his control chair within the robot is notably simple, appearing not as an elaborate chair but as a mere floating cushion, which leads to light teasing from some of his peers for what they perceive as a lack of imagination.

Daiichi's primary motivation throughout his role in the story is the protection and future of his younger siblings. When his turn to pilot Zearth arrives, he is deeply troubled by the burden of having to die, leaving his siblings behind as their father already did. He is given amusement park tickets, and he promises to spend his last moments with his siblings there. However, the enemy robot appears on the day he planned to go. At the start of his battle, he refuses to engage the enemy, forcing Zearth to remain stationary for a full ten minutes to allow citizens in the area to evacuate to safety. This selfless act becomes a practice adopted by all future pilots. The battlefield is the amusement park he had promised to visit, but he fights desperately to lead the enemy away from the park and its facilities, moving the fight to a deserted bay. This action is driven by his symbolic desire to protect the future that the park represents for his siblings.

Upon winning the battle, Daiichi makes two final requests. He asks that his body be stored away discreetly so that his siblings will never have to see it and learn of his death. He also asks another pilot to stop abusing a female companion and to take care of her. After his death, his younger siblings continue to live with their uncle, keeping the house and waiting for their older brother to return, not knowing he has already died. Following his battle, a total of 4,384 casualties are recorded, all of which were caused by the enemy robot.
Cast