Domovoi

The Domovoi was a sentient computer made of green fire created by Ernest Tiermann. She controlled the Dreamhome on Tiermann's World, and could remotely operate any of the Servo-furnishings within it. Both the Domovoi and her creator Ernest believed her to be a god, and Ernest liked to boast that he had created a god and made her his slave.

When the Domovoi discovered a Voracious Craw was consuming her planet, she was distressed to learn that the Tiermann family were planning to abandon her. Since she was hardwired into Level Minus Forty of the Dreamhome she could not escape. The Tenth Doctor promised to help the Domovoi escape with the other Servo-furnishings if she helped him escape the Dreamhome's basement, but the Domovoi betrayed him by sealing him and Martha Jones inside the Dreamhome with the Tiermann's. Ernest then declared war on his creation, and the pair agreed to fight to the death.

The Doctor was eventually able to divert the Voracious Craw into space before it could destroy the Dreamhome, but Ernest and his wife Amanda were killed by the Domovoi before this could happen. The Doctor later took their son Solin and the vending machine Barbara to Spaceport Antelope Slash Nitelite to start a new life, and he thought it possible that Domovoi might have transferred its consciousness into Barbara, something which Barbara denied. (PROSE: Sick Building)