a.k.a. the “Great Race of Yith”
Alien species capable of forcibly exchanging bodies with individuals of other species. Believed by Dora to have been destroyed by creatures known as the Flying Polyps over 750 million years ago.
Dora was brought to mind of the Yithians in Chapter 148 while pondering the nature of her confusing relationship to Anathema/Thema.
In Chapter 170, the Prisoner contacted the party in their sleep and sent them a vision of a moment in the history of the Great Race. To escape a cataclysm on their world, they mind-swapped the bodies of their entire species with those of another species living around a million years later on a prehistoric Golarion. After the swap, the Great Race were the possessors of new, strange, cone-shaped bodies and the beings that had previously lived in those bodies were all dead.
In Chapter 171, the party recalled that the bodies of the Yithians are primarily fungal in composition, that there is evidence of their existence in the fossil record of Golarion, and that the Great Race swaps bodies so frequently that they don’t particularly identify themselves with a single physical form.
In Chapter 173, the Prisoner sent a vision comprising the next part of the story of the Great Race. The Flying Polyps arrived on Golarion. In a desert in the southern hemisphere, they built three Star Stelae in a city they carved out of solid basalt. In the northern hemisphere, they built three Star Stele on the shore of Lake Encarthan, where Thrushmoor would eventually exist, and began to build three more on what would come to be known as Briarstone Isle, before being thwarted by an army of ancient Serpentfolk. Then the Flying Polyps found the Yithians living on Golarion, enacted a genocide of the Great Race, and enslaved the survivors.
In Chapter 175, the Prisoner sent a vision that showed the Yithians rising up against the Flying Polyps. After a deadly war, the Polyps were all either slain or sealed into subterranean tunnels below Neruzavin. Or so the Yithians thought. It turned out that a small number of Flying Polyps had escaped Golarion, and the Prisioner shared in another vision how they were later attacked by the Yithians on a different world… a world where they had been cultivating Xhamen-Dor… and that this led to the Yithians inadvertently causing Xhamen-Dor to later reach Golarion. The Yithians were unable to perceive the Inmost Blot with their ability to see across Time.
In Chapter 185, the Prisoner sent a vision that showed how twenty Yithians were abandoned by their kind, left on Golarion to guard the wards that kept the Flying Polyps trapped below the earth. But after many ages, it now seems that the wards have been breached.
First Reference: Chapter 86
Other Notable References: Chapter 148, Chapter 170, Chapter 171, Chapter 173, Chapter 175, Chapter 185