ONA
Description
Hiroki Wada, known to nearly everyone as Boco, is the central human protagonist of the story. He is an eleven-year-old elementary school student living in Tokyo during the summer of 1989 with his mother, Aiko Wada, who works as a copywriter. As a child from a single-parent household, Boco has developed a degree of independence but also harbors an endearing vulnerability, most notably his frustration over not yet knowing how to ride a bicycle.

Boco possesses a deeply compassionate and fearless nature, often acting on impulse to help others without regard for his own safety. This trait is evident from his first appearance, when he ignores his friends' warnings to rescue a small turtle trapped in the roots of a pond. Despite his small stature and tendency to be unreliable in practical matters, which often worries the adults around him, he has a strong moral core and an unyielding sense of justice. He is also stubborn and refuses to back down from a challenge; even after being bullied and robbed by the older boy Brody, Boco is ready to confront him again to retrieve their money. His compassion extends to his enemies as well, as he refuses to leave Brody behind during a kaiju attack despite their earlier conflict.

His primary motivation throughout the series is the desire to protect his friends and preserve the bonds of their last summer together before they potentially go to different schools. While his mother wants him to focus on summer school, Boco is determined to spend this precious time with his two best friends, Joe and Junichi. As the story progresses, his role evolves from a simple witness to a key figure in the conflict against the kaiju. It is revealed that Boco is a code-holder, a unique individual whose biological signature is the key to a drastic plan by the Eustace Foundation to purify the Earth by feeding him to a kaiju, which would then consume all of humanity. This revelation transforms him from a boy trying to survive into a target that the monsters instinctively seek out.

The most significant relationship in Boco's life is with the giant turtle kaiju, Gamera. After Boco rescues a turtle that later turns out to be linked to the monster, a profound and telepathic bond forms between them. Boco is the first to realize that Gamera is not a mindless destroyer but a protector, specifically of the children. He names the creature Gamera and places absolute trust in him, often pleading with skeptical adults and military personnel to cease their attacks on the monster. This faith is reciprocal; Gamera repeatedly risks his life to shield Boco from threats like Gyaos, Jiger, and Viras. Boco’s bond with his human friends is equally crucial. He shares a particularly deep connection with Joe, a caring and protective friend who ultimately sacrifices himself to save Boco. He is also part of a core quartet that includes the pragmatic and sci-fi obsessed Junichi, as well as Brody, a troubled military brat who initially bullies the group but later becomes a valuable ally.

Over the course of six episodes, Boco undergoes significant development. He begins as a somewhat passive child who is rescued by Gamera, but he grows into an active and courageous individual. When Joe is lost and Gamera is mortally wounded, Boco refuses to give up to despair. He bravely puts himself in harm's way to distract a Super Gyaos, buying critical time for his protector to be revived. His unwavering belief in Gamera proves to be the monster's salvation; when a virus turns Gamera hostile, Boco’s heartfelt words remind the kaiju of his true nature, allowing him to overcome the corruption. By the story's end, Boco has accepted his responsibility as the code-holder and, having witnessed Gamera being reborn in a smaller, juvenile form, declares that it is now his turn to protect the creature that once saved him.

While Boco possesses no superhuman combat abilities, his primary power is his status as the code-holder, which makes him a living key of immense importance to the Eustace Foundation's global plans. This status also appears to create a psychic or empathic link with Gamera, allowing the two to understand each other on a level that other humans cannot. His true strength lies in his emotional resilience, his ability to inspire loyalty, and his unshakeable faith in the bond he shares with the giant monster.