Bio Saurus rule the continent of Poseidon, a flat jungle dotted with lakes and veined with rivers ideally suited for dinosaurs. Once a peaceful species that roamed the jungles in large herds, these once-dinosaurs were recruited by Vondar to help the good Bio Ninjas battle the dark Bio Ninjas. In their dinosaur state, they were too weak to help the good Bio Ninjas battle against the strength of the dark Bio Ninjas; Vondar therefore transformed each of the dinosaurs into fierce and powerful warriors made of half flesh and half mechanical bionics, giving the good Bio Ninjas a strong ally.

Tyrantus, the most powerful Bio Saurus and leader of their army, uses his razor sharp Tyrannosaurus Rex teeth to tear enemy warriors to pieces. Tyrantus’ second in command, Tricerivon, uses his massive horns to ram the enemy and crush approaching threats. Rapticus, a Velociraptor capable of running at the speed of sound, is used by the Bio Saurus army for reconnaissance missions.