When a radioactive cloud threatened their civilization, the Thelemites devised a desperate plan to save themselves. Discovering the native flora wouldn't be harmed by the radiation, the Thelemites placed their minds into the plants. To preserve their bodies, a cell was taken from each citizen to build the cyborg, Zar-Tan.
After the radiation had dissipated an unknown time later, the Thelemites discovered the Terralyns had colonized the planet. Zar-Tan viewed the Terrlyns as a threat and began attacking them prior to stardate 2314.6. Attempting to communicate with both Zar-Tan and the Terralyns, the Thelemites learned the best they could do was form a "thought image" of a woman, refered to as "The Ghost". In this form, the Thelemites were able to stop Zar-Tan's attempted destruction of the Terralyns. With the help of the crew of USS Enterprise, the Thelemites were restored and now share their planet and technology with the Terralyns and the Federation. (TOS comic: The Empire Man).