Beast-Lord was a designation bestowed upon the leaders of both the Beast Riders and the Untamed factions residing on Onderon.
The initial assault on Iziz, Onderon's capital, was spearheaded by Beast-Lord Kinch Sunka, thereby initiating a prolonged state of conflict on the planet. The most renowned Beast-Lord was arguably Oron Kira, notable for marrying Princess Galia of Iziz and successfully unifying the populace of Onderon.
Following the Untamed's capture of the Ancient Proving Grounds from the Sith, the location became a testing ground for Beast Riders aspiring to the rank of Beast-Lord.
Brutann, the Untamed's Beast-Lord, served as a Sith within the reconstituted Sith Empire during the era of the Cold War, ultimately meeting his demise on the icy world of Hoth. His sibling, Beast-Lord Akoru, commanded the Untamed forces on their homeworld.