Boo is one of the youngest soldiers conscripted into the army of Hellywood, the fortress city ruled by the dictator Hamdo. His exact age is not specified, but he is noticeably younger than his peers and is among the most junior members of the child soldier corps.

In terms of background, Boo is presumed to have been kidnapped from his home village, which was almost certainly destroyed by Hellywood's forces. Like all the other child soldiers, he was told he would be allowed to return home if he served the army well, a lie that fuels his daily actions and hopes for the future.

Boo's personality is defined by his timidity and innocence. He is a very kind and gentle boy, but he is also deeply frightened and confused by the brutal world he lives in. In critical moments, he often freezes up from fear, unable to act or fire his weapon. For example, when he first encounters the protagonist Shu, he is unable to shoot and simply lets him escape. His youth has left him vulnerable to the corrupting influence of King Hamdo's regime, leaving him uncertain about basic concepts of right and wrong. However, his inherent innocence means he is more receptive than others to ideas of peace and criticism of Hellywood's cruelty.

Boo's primary motivation is simple: he wants to survive the war and return to his village. He fights not out of loyalty to Hamdo or any ideology, but because he has been told this is the only path home. This shared dream of returning to a normal life is the central reason he endures the horrors of his existence.

His role in the story is primarily as a supporting figure among the group of child soldiers. Although he is initially loyal to the army out of fear and a desire to follow orders, his character arc involves a gradual awakening. Through Shu's influence, Boo begins to question the orders he is given and the morality of Hellywood's actions. In a significant act of defiance, he helps Shu escape from prison by giving him his own wooden katana, a small but meaningful gesture of rebellion.

Boo's most significant relationship is with his fellow soldier Nabuca. Nabuca acts as Boo's primary caretaker and protector, treating him like a younger brother or even a son. Nabuca constantly worries about Boo's well-being, spares him from the most difficult tasks, and speaks to him with unusual gentleness. He even keeps Boo's acts of rebellion secret to protect him from punishment. For Boo, Nabuca is a source of stability and safety in a chaotic and violent world. Boo also develops a connection with Shu, the outsider from another world, whose non-violent philosophy and clear sense of justice resonate with Boo's own confused feelings, making him the first among the child soldiers to truly doubt Hellywood.

Boo's development is cut tragically short. As the story progresses, he becomes more questioning and aware of the wrongs around him, moving away from his initial passive obedience. In a climactic moment, he demonstrates his complete transformation by performing a heroic sacrifice. When he sees that Soon, another character, is about to shoot Nabuca, Boo steps between them and takes the bullet himself, dying to save the person who had always protected him. His death is a profound and heartbreaking moment that deeply affects Nabuca and reinforces the series' themes about the cost of war on children.

Regarding notable abilities, Boo possesses no superhuman or special powers. As a child soldier, he has basic training in handling a firearm, but his timid nature often prevents him from using it effectively in combat. His most defining ability is not a physical one but a moral one: his capacity for kindness, empathy, and the courage to ultimately sacrifice himself for a friend.