Oni first unveils, 2 years prior to the storyline, in his match against Byoudouin Houou. His form takes the form of a demon god. Oni's name means Demon. Two years later, Byodoin's own Inner Self takes the form of a skeletal Pirate, first shown in his rematch with Tokugawa. He is described as "Pirate of Japan". Ryoma's own Inner Self takes on the form of a samurai, greatly resembling his father, Nanjiro Echizen. He is know as "Samurai Junior".