Shahryar suggests for Riku to scout for an experienced Diver to join his Force, starting with the person who build Momo's rental Kapool. Riku, Yukki, and Momo visit Nanami's brother Koichi Nanase and invite him to join their Force, but he declines their invitation, as he has retired from Gunpla Battle. They learn from Nanami that Koichi retired four years ago during the time GBN evolved from the physical based GP Duel (GPD), when his teammates left him and he fell into a state of depression. Upon hearing from Riku that Shahryar still praises him, Koichi enters GBN to learn more about Riku and his Force...