Carl, the Evil Cockroach Wizard (who tends to shout out his name as much as possible and always wants to be called Carl the Evil Cockroach Wizard), continuously schemes to defeat Yin, Yang, Master Yo and the power of the Woo Foo with his insecure genius. It is undoubtedly the greatest enemy of Yin and Yang, but also one of the most pathetic, with Zarnot and Ultimoose. He also lives with his overbearing mother Edna, who is a dragon (it makes no sense as to how they are all related). Carl is always trying to find a way to impress his mother and out-do his brother Herman. Despite his desire to win his mother's love, Carl is resentful and has talked back (usually under his breath), made her cry, and even put a spell on her. And yet, he has been accused of being a mama's boy (obviously by someone who doesn't know him at all). Even though Carl and Herman dislike one another, they have worked together on occasion, making a deadly force against Yin and Yang. His dream was to become so enormous that he would blot out the sun, an idea that Herman and the Night Master stole. He eventually saw someone and got over it. Carl is an anti-thesis to Yin's magical ability and Yang's goofiness. Carl is stronger than Yin and Yang in power, but if someone criticizes him, he's easily distracted. It is revealed in Yin Yang Carl that he could defeat Herman in a fight, if only he used his magic, calling into question why he never has (Yo was in Carl's body, fighting with Carl's powers). Because in the past he has shown desire to get along with Herman (Dojo Alone and Family Day), it could be because he loves his brother. He has an ad on a dating site. In "Creeping with the Enemy," Carl is the only villain not recruited into Eradicus' company Eradicorp cause Ella states that a cockroach working in a coffee shop would not do well for the business.
Carl is one of few that some other high-rank Org villain view him as the weak one, but instead, he has few trick under his little bug body than meet the eye, if only his ego didn't get in the way.