Juliu Epreto was a Nooman male. He wanted to free the people of his world from the cycle of Holy Biology. He discovered that the "Sun" was a spaceship. He planned to use a poison to kill the Sky, an intervening membrane. Then he reach the ship and take the Noomans to another planet.
The Third Doctor tried to convince him that their biology was tied to their planet, and departing would kill them, but Epreto did not believe him. While he was carrying out his plan, the base drive for Promotion overtook him. He killed one of his fellow males and ate his heart, then cocooned himself. Emerging as a naieen, he had a change in perspective and decided to work more calmly towards his goals. (PROSE: Speed of Flight)