The Big Bad Four are Moo's top generals who report directly to him during his takeover of Pangaea. In the Japanese dub, they are known as the Four Heavenly Kings, not to be confused with the level bosses from Monster Rancher DS. In addition to ruling over large force of armies, each of them is also a powerful monster in their own right, capable of going against the Searchers and even Moo himself in his strongest form.
Members
- Pixie: Has a home base in a castle on Ancra, from which Moo intends her to take over Bubalook and Aurora Islands, with her loyal friend and aid Big Blue serving as her right-handed man. Having been treated horribly by the human in the past, Pixie joined Master Moo in his conquest to create a world where monsters rule over humans. She is the only one of the four to defect to the good side and also the only one that does not die throughout the series.
- Gali: His lavish palace lies disguised somewhere in the Takrama Desert, and his domain covers the most of Rema. His troops patrol not only the jungles and forests but also the deserts and the waters surrounding the country. Of the four, Gali has the most diverse tactics and techniques.
- Gray Wolf: Rules from a large ice cave positioned at the base of Mt. Salem, halfway up the Northern Continent. His troops are responsible for the mountain regions in that area, and in order to keep control they run regular raids on villages, destroying everything and leaving only weak survivors. Gray Wolf is the only member of the four to have been brainwashed into joining the Baddies. He is also the fastest and most agile.
- Naga: Naga's Castle is built atop a steep grade in the Papas Alps to ensure he can keep a close watch on the surrounding area. From this vantage point, Moo uses his forces to subdue the Nettle Kingdom and most of Brillia. Naga is the highest ranked of the four and the most physically powerful, mature and serious. His minions are also the strongest and most experienced.
- While he was not included in the Big Bad Four, General Durahan is also one of Moo's top baddies, and was responsible for the takeover of the entire Eastern Continent.