Morag was a younger son of Grekk. He had red hair. He and his brothers were left on a planet by their father, where they waged war against the planet's other inhabitants (urged on by Deemon), keeping their captured enemies in the Pit.
When the First Doctor arrived in their castle, Morag accused him of being a spy for the Crustians, and mocked the TARDIS when he claimed it was his spaceship. He took the Doctor to the Pit on Swarf's orders. He and his brothers later tried to kill their prisoners when they detected a radio transmission from them to the Crustians, but were caught in a trap in prisoners had made. The Doctor hoped that the sons of Grekk, now prisoners themselves, would rethink the need for peace on their world. (PROSE: The Sons of Grekk)