Mad Jack

Mad Jack is an antagonist in Samurai Jack. He is the embodiment of Jack's inner darkness, temporarily given form by Aku to defeat him using his own skills against him. He made his first appearance in Episode VIII: Jack versus Mad Jack. He lost his physical form after Jack found peace within himself and caused him to disperse. When Aku destroyed the last remaining time portal, Jack's inner anger and frustration caused Mad Jack to resurface as Inner Jack, where he continued to antagonize Jack in his mind during most of Season 5.