Essentially a god-king, the Supreme Overlord was the Yuuzhan Vong's link to their gods, and the only one capable of addressing Yun-Yuuzhan. Succession was not hereditary, and future Overlords were chosen from a pool of candidates whose births were signified by omens, prophecy, and noble lineage. The birth of twins was very rare among the Yuuzhan Vong; in each case, the twins would fight to the death at age seven, with the victor later becoming Supreme Overlord.
All of the candidates were trained in all aspects of Yuuzhan Vong society, and each treated as if he was the heir apparent. The Supreme Overlord often assumed power through the murder of the current Overlord. The Overlords wore ceremonial robes made from the flayed and preserved flesh of Steng, the first Warmaster, and Yo'gand, the first Supreme Overlord, who battled each other in the Cremlevian War which united the Yuuzhan Vong. On their ascension, the Supreme Overlord was ritually scarred and modified, sacrificing several external organs and limbs to make him resemble Yun-Yuuzhan.
Politically, the Overlord held authority and power as Intendant caste and Warrior caste, and supreme religious leader (Priest caste), standing higher than the High Prefect, Warmaster, and High Priest.
Shimrra Jamaane was thought to be the final Supreme Overlord—it was he who instigated the invasion of the galaxy a millennium after the Yuuzhan Vong left their primordial homeworld in ruins to seek out a new home. It transpired, however, that Shimrra was but a puppet, controlled by the true power behind the throne, Onimi. The true Supreme Overlord was killed by Jacen Solo onboard Onimi's escape capsule over Coruscant. Following the deaths of Onimi and Shimrra, the Yuuzhan Vong were without a Supreme Overlord for the first time in their history.
- The New Jedi Order Sourcebook
- Coruscant and the Core Worlds
- Ultimate Alien Anthology
- The Official Star Wars Fact File140
- The New Essential Chronology
- The Complete Star Wars Encyclopedia
- The Essential Guide to Warfare