Za

Za was the leader of a primitive tribe circa 100,000 BC To preserve their power and authority, the leaders of the tribe had kept a monopoly on the secret of making fire, with the secret and leadership being passed down from father to son. Unfortunately, Za's father was killed during a hunt before he could pass on the secret. Unable to make fire for his people, Za found his leadership in jeopardy, moreso with Kal, an outsider taken in by the tribe, hoping to take over.

Za's fears seemed confirmed once Kal had captured the First Doctor, claiming that he had seen the old man make fire. Za ordered the stranger and his three companions imprisoned in the Cave of Skulls, hoping to wrest the secret of fire from them before Kal could and so stay in power. When the strangers escaped, Za pursued them together with his mate Hur, and when Za was attacked by a forest animal, these strangers tended to his wounds.

Despite this, Za still had the strangers reimprisoned, and even after they taught him the secret of fire and helped him defeat the would-be usurper Kal, Za still refused to release them.

Eventually the strangers managed to escape again, and when Za led the tribe in pursuit of them, he was able to see the strangers enter their strange blue tree, which vanished into thin air even as his men prepared to throw their spears. (DW: An Unearthly Child)