Gundam Build Fighters

In a near-future world where competitive GunPla Battles have gained global popularity during the "Second GunPla Boom," a middle-school student named Sei Iori, who is skilled at assembling GunPla but lacks battle experience, meets a mysterious boy named Reiji. Reiji is a skilled Gundam Fighter. The two join forces with the goal of competing in the GunPla Battle world championships.