The protagonist of this story, a 13-year-old first-year middle school student attending Misora Second Junior High. He is the son of Junichiro Yamano, the developer of LBXs. He has a gentle but brave personality and cares deeply for his friends, making many allies through LBX battles. He has a robot-geek side, loving not just LBXs but all kinds of mecha and plastic models, and often hangs out at the local Kitajima Model Shop with his friends. Perhaps influenced by his father, his passion for LBXs is stronger than anyone's, and he shows open rage toward the organization "Innovator" that misuses LBXs.

A first-year middle school girl in the same class as the protagonist, Ban Yamano, and also his neighbor. Her trademark is her earmuffs, and she wears glasses at home. She is a model student liked by her classmates and teachers alike. She also happens to be liked by a string of eccentric males like her classmate Ryu Daiguji, Otacross, and Ota Yellow. She possesses extensive knowledge about LBXs, teaching Ban various things and providing support during battles.

A first-year student at Misora Second Junior High and an LBX friend of the protagonist, Ban Yamano, from the neighboring class. Commonly known as "Kazu." Though he looks a bit like a delinquent, he is actually a "good guy" who gets along well with others. Despite his appearance, he has a slightly timid side and can flinch in the face of powerful enemies or critical situations, but he possesses the courage to stand up no matter how scared he is for the sake of Ban and the friends who believe in him.

The rival of the protagonist, Ban Yamano, and the scion of the world-influential Kaido Financial Group. He is actually one of the survivors of the Tokio Bridge collapse accident, where he lost his parents; he was taken in by Yoshimitsu Kaido and raised as his grandson. He temporarily transferred to Misora Second Junior High, arriving by jet fighter. He has a very cool personality but speaks with polite language. Accordingly, he uses the polite "boku" for himself. He refers to Ban Yamano as "Ban-kun."

A third-year middle school student and the leader of the "Four Kings" delinquent group at Misora Second Junior High. He makes the slums behind the gym his base. He sports a classic delinquent look with a long school coat over his bare chest and wooden clogs, and he carries a wooden sword. His father is the head of Prometheus Corp, and his LBX, Hakai-O, is a Prometheus product. He was feared as the "God of Destruction from Hell" due to his combat style of ruthlessly destroying opponents' LBXs, but he has a manly and caring side, making him well-liked by his subordinates. After losing a battle to Ban, he acknowledges Ban's skill and cooperates as an ally from then on.

A third-year middle school student. The leader of the delinquents at Misora First Junior High. Aged 15, turning 16 in W. A highly skilled LBX player feared by the nickname "The Magician in the Box." He has the ability to simultaneously control three Jokers, which are known for being particularly difficult to handle. He is aloof yet proud, a nihilistic individualist. He also has a bellicose side, willing to sacrifice allies to win a match. He always carries tarot cards and often speaks in prophetic riddles related to them. He is the complete opposite of Hanzo Goda, who runs Misora Second, in terms of personality and fighting style, and the two are constantly in conflict.