The Nine Demon Warriors are a group of demon-like experiments who once ruled the Galactic Alliance and the Earth. Each demon represents an element (e.g. fire, earth, water, etc.), and have been shown to be able to take on human guises. They were all sealed in separate portals by the warriors using special items, although the portals can be re-opened using an item called the Genetic Box which is essentially a mechanical puzzle box containing maps to the portals' locations.
- Leroy (voiced by Wally Wingert) - He is essentially the most aggressive and the nastiest of all of Dr. Jumba Jookiba's experiments. This creature's appearance is virtually identical to 626's normal and combat form except for the bent antennae, yellow teeth, frilled ears, and red fur. His true form (Leroy absorbs a energy powers from the Spirtual Stone): a giant red muscular monstrous demonic dinosaur/dragon/lizard-like creature version of himself with the slightly humanoid upper body, his head is bald, his face is reminiscent of the features of a Tyrannosaurus, a crocodile, and a dragon with his reptilian heritage underlined by his slithering tongue, the reptilian dinosaur-like tail, a volcanic pits on his back, a three-toed elephant-like feet, and red scales, similiar to Chaor from Chaotic. He has the element of fire. His sidekick is Reloy.
- Thundar (voiced by Paul St. Peter) - He is the elemental of Thunder. He is a large, blue-skinned reptilian ogre/koala-like experiment with an arrogant and impatient attitude, and shows a deep dislike for his own brother Leroy, seeing himself as Leroy's master rather than a brother. He possesses the ability to control electricity. He is similiar to Tchang Zu from Jackie Chan Adventures.
- Earthquark (voiced by Frank Welker) - He is the elemental of Earth. Earthquark resembles a large, humanoid Triceratops with the Evile (627)-like ears, the reptilian face and two prominent fangs jutting from his lower jaw. He has the firm dislike for Leroy (perhaps the greatest hatred for him out of all the demon warriors), the camara (a flashing light makes him confused), and flowers which are also the special item used to banish him originally. He is shown to be able to dig underground and move like a shark, his horns visible above ground when he digs. He is similiar to Dai Gui from Jackie Chan Adventures.