Діо

A robot built identical to Casshern, he, along with Casshern and Leda, were sent to kill Luna, but Dio failed to reach her before Casshern. He plots to halt the ruination by exposing Casshern's secret and rule the world, taking the place of Braiking Boss. As such, he attempts to organize a robot army. He holds animosity towards Casshern, as they were both created with identical specifications, but Casshern was slightly ahead of him in reaching Luna, and now appears to be immortal.