The Captain was a feared space pirate who ruled the planet Zanak, assisted by his nurse and Mr Fibuli. He also had a pet robot parrot, Polyphase Avatron. He commanded the Vantarialis until he crashlanded on Zanak, where he was rebuilt as a cyborg. The Captain designed the transmat engines which allowed Zanak to materialise around other planets and plunder their mineral wealth, and he kept the super-compressed remains of those planets in a trophy room. The Captain's nurse was actually a projection of Zanak's former queen, Xanxia, who was controlling the Captain and using the energy from the planets in an attempt to grant herself immortality. After Calufrax was plundered, the Doctor investigated and, with the aid of the Mentiads, fought against the Captain, preventing him from attacking Earth next. Xanxia killed the Captain when he turned against her.