Some time before Kris and Susie entered the Dark World, Jevil worked as the Court Jester alongside Seam, who was the Court Magician. One day, however, Jevil encountered a "strange someone," and his personality shifted permanently. Seam explains that Jevil "started saying bizarre things that didn't completely make sense – but didn't completely not make sense, either." Eventually, Jevil started viewing the world as a game, and everyone else as its participants. He was also said to have informed King of the Knight and his plan. When his insanity got out hand, Seam tricked Jevil, and locked him away underneath Card Castle.
