Martinius

Martinius was the leader of the black-haired people of an Earth-like planet. The Second Doctor urged him to free the fair-haired people from slavery, and while he argued that the slaves were treated well and were physically inferior, he said that they would be freed if they could pass the tests of Trefus. After the slaves passed the tests, he said that they would keep their promise. (COMIC: The Tests of Trefus)