When the Ancestral Race colonized Thalea, they resembled Ritjessians at first. Since they were efficient in technology, climate control towers were constructed. These towers were spread everywhere and kept the world of Thalea in a livable state. They harnessed their own Dark Matter energy, but instead of using the power in outward bursts, they developed the conversion process of the energy into a physical form. Civilizations were created, but after the Ancestral Race ascended from Thalea, there was no one left to govern the ones left behind. There were not enough people to maintain the climate towers either and the towers ceased function. The planet's weather reverted back to ice and snow.
Because of this, Thelians' appearance began to evolve. Their light skin became darker to absorb heat efficiently, and the skin and fur on their bodies grew thicker to fight the cold. The remaining Thelians fought for power for years on end. In the process, the control towers were turned to ruin. When the warring did finally end, the cities sat dilapidated and the survivors regretted it all. Technology didn't solve anything so they started a new, simple lifestyle - only keeping what was needed to survive. The civilians converted the ruins of Thalea into make-shift housing. All usage of Dark Matter powers became outlawed and over the next hundreds of years the abilities were also lost to time. The Thelian symbol was branded into society as a reminder of the past as it resembled the eye rims their ancestors had before them.