The Terralyns are a humanoid species that live on planet Terrellian II. The previously nomadic people colonized the seemingly abandoned planet some three generations prior to stardate 2314.6. After being attacked by Zar-Tan, it was learned the planet's previous occupants, the Thelemites, were still on the planet in the form of plants. After the Thelemites were returned to humanoid form, both peoples agreed to share the planet. (TOS comic: "The Empire Man").