Theros is the fourth planet orbiting the star Haelos. It is the middle of three life-bearing worlds within the inner solar system, the others being Elrune and Aloris. It is the most similar planet in the Haelos system to Earth. Unique to Theros among the other life-bearing planets is the sheer amount of sophonts that have evolved on the planet. There are sixteen species of sophonts currently known to inhabit the planet.