The Wasilsi were an ancient phoenix-like species once native to the planet Jaska III, but eventually died out. Xenoarchaeologists have discovered that the Wasilsi were enemies of the Tikiarri, and that they were much larger and stronger than the Tikiarri. However, for unknown reasons, the Tikiarri survived while the Wasilsi disappeared. Many scientists suggest a plague spread across Joralla, but only affected the Wasilsi. Others claim that the Wasilsi were "seeded" on Joralla as part of an experiment, but their immune systems were unable to counteract the viruses of the jungle.