Tekapesh, from Martian Dreams
The Avatar first encountered Tekapesh in Elysium, where the hero learned from him about his race's past and near-extinction from a centuries-old plague, which they avoided by escaping into the Dream-World by using their Dream Machines. When the humans from the 1893 expedition attempted to use the machines, Tekapesh and his grovemates took over their bodies, leaving their minds trapped in the Dream-World. Tekapesh was dedicated to resurrecting their "true" Martian forms, and he the members of his grove were unwilling to relinquish their human shells until they could find a way create new bodies to inhabit.
After consulting with the Martians still inhabiting the Dream-World and speaking to both George Washington Carver and Cheshef, the Martian occupying Carver's body, the Avatar was able to grow a new body from Martian seedlings, which Prektesh was able to inhabit. Unfortunately, this quickly led to the realization that the ancient plague still infested the martian soil, which became apparent when Prektesh began to wither and eventually perish. Before dying, Prektesh told the Avatar to seek out Xaktsesh in the Dream-World, and ask of her podmate's experiments in creating artificial bodies.
Saddened at Prektesh's loss, Tekapesh showed renenwed interest in the possibility of using artificial bodies, and agreed to allow the Avatar to use their Dream-Machine to free the trapped humans in order to learn more. The hero was successful, and Tekapesh honored his agreement, allowing the humans to reclaim their bodies, while he and his grovemates returned to the Dream-World to await the Avatar's new solution.
Eventually, the Avatar was eventually able to successfully transfer the consciousness of Chsheket into an inert robotic body, providing a way for all the Martians to exist in the real world again.