Sanada's twin, along with his brother Sanada Yukio, are two of Shun's group's contrincants on the other side of the line while playing Shouben kouzou. They kill the rest of their team and appear to be very strong and fast. Along with Shun's group, they win the game and pass on to Urashima Tarou's castle. However, Yukio's twin dies when he picks up the cross from a bowl Tarou gave them.
Yukio's twin was always bossing Yukio around and telling him what to do. Although Yukio's twins name was not mentioned in the manga, also Yukio's twins last is the same to Yukio.