A Zarthan is a race of aliens from Zartha. What the Zarthans look like is unknown, as all the ones that have been seen were disguised as humans. The Zarthans have a force known as the Light of Zartha, which protects their planet. However, the Kylothian Serleena wants the Light to destroy the planet. However, princess Lauranna left the light with Kay, who led Serleena away by pretending to launch the light away.
- The Zarthans have some form of rivalry with Kylothians, as they for some reason want to destroy Zartha.