Leela

Leela was a warrior of the Sevateem and she was nominated as their leader. She forces her way into the Tardis rather than staying and being the Sevateem leader. Leela thought that "if in doubt, kill it", she wore animal skins and she was refered as "savage" many times by the Doctor and other people. Leela's instinct often saved the Doctor, because she could use many weapons, but her best was her knife that she always carried with her. Having helped to defeat the Sontaran invasion on Gallifrey, Leela decided to stay on Gallifrey with Andred and K9.

The Sevateem was one of two tribes, the other being the Tesh. The primitive warlike Sevateem inhabited the jungle and they worshipped the god Xoanon.

The Tesh where the enemies of the Severteem, and their ancestors had been technicians of an Earth spaceship from which both of the tribes came from. The Tesh had remained in their ship and they developed telepathy and mind control. They also worshipped the god Xoanon. 

Leela was in The Face of Evil to The Invasion of Time