The Beast Wars of Onderon were a conflict fought in the centuries between the Great Hyperspace War and the Great Sith Wars. After defeating his master, the Dark Lord Naga Sadow, the Sith Lord Freedon Nadd settled on Onderon and become the tyrant in the capital city of Iziz. He infused the culture of the city with the ideals of the Sith, turning it into a Sith-led world.
During his reign, Nadd exiled the city's criminals into the dangerous jungles of Onderon where he expected them to be killed by the beasts who lived there. Rather than be killed, however, many of the criminals survived and came to tame the creatures. These criminals became known as Beast Riders and formed their own gang of gureilla soldiers, eventually waging war against Iziz and the Sith Lord who had exiled them. The Beast Wars lasted even after Nadd was killed.
- Star Wars: Knights of the Old Republic II: The Sith Lords (First mentioned)
- Star Wars: The Old Republic (Mentioned only)