Caius the Shadow Monarch, known as Wicked Emperor Caius in the Japanese version, is a character version of the card, "Caius the Shadow Monarch". He appears in the video game Yu-Gi-Oh! 5D's World Championship 2009: Stardust Accelerator. He and Dark Armed Dragon can be unlocked as Tag Duel opponents. To do this, the player must win 3 Tag Tournaments.