無敵鐵金剛
In the Mazinger Z Infinity feature film, which renders the Grendizer story as Non-canon in the terms of the TV series of Mazinger Z, Koji spends the next 10 years of his life after the fall of Mycea as a scientist much like both his father and grandfather, eventually returning back to Mazinger Z to fight one last battle against Dr Hell and his armies over a new, seemingly all-powerful Mazinger.