Yu

Yu (ユウ): Yu is a young boy who, along with his grandmother, encounters the Oni Brothers and then Ryotaro. While his father is on business in foreign countries and his mother dead while he is away, Yu is sent to the countryside to live with his grandmother where he does not make many friends in school. He encounters the Oni Brothers when they come to the countryside to steal the Trump Stone. He joins the DenLiner crew when he forms a contract with Deneb so the Imagin can help fight the Oni Brothers. During the epilogues, it is later revealed that Yu is actually Yuto Sakurai as a child.

Yu was portrayed by Ruka Sawaki (沢木 ルカ).