Spirit Talkers

The Spirit Talkers was one of the oldest civilizations in PoC, estimated to have existed for several millennia before the Ymaryn made contact via a trade mission.

Had a major natural wonder/megaproject known as the Cave of Wonders, which held religious significance. It is currently sealed and long lost.

Fought with the Dead Priests (Xohyr) and the nomads regularly. After they were destroyed, their land was eventually settled by Thunder Horse (Now Thunder Speakers).

Used elite beserker-type warriors, which caused morale damage to enemies. However, since their military was mainly composed of only or mostly beserker-type warriors, they were extremely fragile, which was one of the contributing cause leading to their downfall.

History
They first encountered the original Thunder Horse in Lowlands rampage as a victim of their rampage.

Downfall
The Spirit Talkers, perhaps unwisely, decided to claim in What's that in the sky? that they made the comet appeared in the sky and that they held the sacred Star Axe, which caused the Thunder Speakers to ask for help from the Ymaryn.

While the Thunder Speakers and the Ymaryn were responsible for the event that led to the destruction of the Spirit Talkers, they were only a proximate cause. The ST was deeply afraid of taking on new ideas and taking damage to their stability, which caused them to be extremely fragile. They also used elite beserker-type warriors, which were much smaller in number, and made them fragile militarily.