A second-year student who has transferred to Seiho Academy middle school, and a master of the Jigen Haoh school of martial arts. Sekai's encounter with Fumina Hoshino introduces him to Gunpla Battle, leading him to discover how enjoyable and deep it can be.
A second-year student at Seiho Academy middle school, and younger brother of China Kousaka. Yuuma is a gifted young Gunpla builder, with enough talent to win the Grand Prix in a modeling tournament's Artistic Gunpla Contest.
A third-year student at Seiho Academy middle school. Fumina is president of the Gunpla Battle Club, and is busy trying to collect members for her club, so that they can compete in the middle and high-school division of the Championship.