Gundam Build Fighters S00 E05 GM's Counterattack

Nils Neilsen invites Sei Iori, Meijin Kawaguchi and the rest of the group to Yajima Stadium in order to try out his new large-scale battle system. Sei is just about to unveil the improvements he's made to his Gunpla, when a mysterious group appears and challenges them all to a Gunpla Battle!