Yuuri is Yukiko Shirato's bodyguard and the current champion of Megalolania, a massive megaloboxing tournament headed by the Shirato Group. He seeks out the underground fighter Junk Dog (Joe) after he had insulted both him and Yukiko, meeting him in the underground ring where he easily defeats him and challenges him to work his way up to Megalonia if he wants to fight him again. Yuuri is equipped with a unique prototype state-of-the-art "integrated" Gear, which is surgically grafted directly to his arms.