Soldeed

Soldeed was the last surviving scientist of the planet Skonnos. He worked for the Nimons.

He negotiated an agreement with a Nimon that would give his people the ability to conquer the galaxy. He was utterly devoted to the Nimons, believed wholeheartedly that they would fulfill their part of the agreement and would chastise anyone who would question them. The Nimons trusted only him to enter their presence; anyone else would have been executed.

However, he was disappointed by the Nimons' refusal to advance him any further technology when the last shipment of sacrifices was lost. When the Fourth Doctor and Romana appeared on the scene, he mistrusted them and tried to have them sentenced to death in the Nimons' complex. Afterwards, the discovery that the Nimons had been lying to him and intended to invade drove him raving mad.

Blaming the Doctor and Romana for interfering, he tried to kill them both as well as reverse everything the Doctor had done to prevent the Nimons from coming through their Black hole. He was shot dead by Seth. (DW: The Horns of Nimon)