Zach Varmitech

Zach is a robotics inventor who has a rivalry with both Aviva and the Kratt brothers. He grew up alongside the Kratts and met Aviva at summer camp. He claims to be the world's greatest mind. He tries to develop hotels and vacation spots all over the world by controlling creatures' minds and using them as workers. However, his plans are always foiled by the Kratt Brothers. He always screams when he sees an animal, hinting that he has a fear of all animals. He does not know much about the animals he captures, often mispronouncing their names. As a running gag, he calls the Kratts "Wild Ratts", with the Kratts usually correcting him.

Chris and Martin’s rivalry with Zach is surprisingly friendly and comedic, due to the Kratt brothers’ forgiving nature, even though Zach has tried to kill them several times throughout the series. He is always designing robots, usually around animals. His most frequently seen invention is the Zachbot. Although he has a house in a neighborhood, he also has a skyscraper located in New York City (as seen in "Falcon City"). This skyscraper is where the Zachbots are produced. When travelling long distances, he uses his jet. Otherwise, he usually rides on the shoulders of a Zachbot.

He's also scared of the dark (as seen in "Platypus Café"). He gains fear of animals like moon rats in "The Gecko Effect" and a Gila monster in "Gila Monster Under My House". His favorite soup is tomato soup in "Skunked" when he smelled it and ordered a Zachbot to have it, even though it chases him when he got sprayed. Out of the most episodes, Zach is known for attempting to commit acts of crime, which includes piracy, as shown in "The Gecko Effect," "Race For The Hippo Disc," and "Skunked," portable hacking in "Creature Power Challenge," attempted breaking and entering in "Bandito: The Black-Footed Ferret," skyjacking in "Osprey," and he acts like a hacker in "Mosquito Dragon."