In the 2011 Animated Series, through a descendant of the Lizards that were enslaved by him, Slythe serves Mumm-Ra in order for his kind to take revenge on the ThunderCats for generations of persecution. Succeeding in ransacking Thundera, Slythe pursues Lion-O's group before overseeing the search for the Book of Omens and later the War Stones. When it came to the attack on the Elephants' village while Mumm-Ra was in the Astral Plane, Slythe and Grune disobey Mumm-Ra's orders and attacked the village. In "Legacy," it was revealed that a Lizard named Rezard assisted Leo and Panthera into overthrowing Mumm-Ra. In "New Alliances," some of the Lizards that worked for Slythe have been deserting Mumm-Ra causing Slythe to prosecute any that he catches. Slythe is also instructed by Mumm-Ra to recruit Kaynar and Addicus to Mumm-Ra's services.