Kamen Rider Kiva Episode 15

In 1986, Ramon and Riki tell him to get them involved because of their endangered status, Jiro thinks back to his Race's slaughter and his intent to kill the one responsible: the mysterious the Rook of the Checkmate Four, the elite branch of the Fangire Race. In 2008, Wataru and Shizuka encounter a childish man who is drowning in a river, saving him. Asking how he is, the man ask for their help as he has no memory of he is. Deciding to help him, Wataru brought the man home, only for him and Shizuka to deal with re-teaching the man how to eat before naming him "Dai-Chan".