The Stopped Heart

The only two Buranki currently on Earth that possess a beating heart are Oubu and Entei. What's more, Reoko has defeated the headless Buranki, also called the "déraciné," and obtained its heart. One man declares this a situation that cannot be overlooked, and sends several Bubuki users to Japan in order to reclaim the stolen heart. Meanwhile, as Azuma and his companions continue to ride the Buranki transport train, a man carrying a guitar shows up in front of them and forces Hiiragi to slam on the brakes. Just who is this man?