D is for... Delta Magnans

Green-skinned humanoids who originated on the planet Delta Magna. When this planet was colonised by humans from Earth, the Delta Magnans were forced to relocate to the planet's third moon. This world was covered in marshland - leading the colonists to nickname them "Swampies".
A deeply superstitious people, they worshiped a god named Kroll. who appeared as a massive squid. Ancient texts claimed that Kroll had grown to enormous size after swallowing a sacred idol belonging to their priests. During the leadership of Ranquin, the humans set up a methane refinery on the moon. Ranquin set about buying weapons from a gun-runner named Rhom-Dutt, so that they could attack the refinery and drive the "Dryfoots" from their home - unaware that Rhom-Dutt was secretly working for the refinery boss Thawn. He wanted to wipe out the "Swampies", and their having guns would give him an excuse to do so. Romana was captured and was to be sacrificed to Kroll - but this proved to be a man in a costume. The real Kroll was awakened by the activity of the refinery. Ranquin believed that he would be protected from it, but was killed. The Doctor deduced that the idol which the creature had swallowed was the Fifth Segment of the Key to Time. The tracer reduced the monster to thousands of ordinary squid - a food source for the Delta Magnans. As Kroll had been responsible for the methane levels, its destruction would have meant that the humans would have little need to disturb them further. Their new leader was the more progressive Varlik.

Played by: John Abineri (Ranquin), Carl Rigg (Varlik), Frank Jarvis (Skart), Terry Walsh (Mensch). Appearances: The Power of Kroll (1978 / 9).

• Ranquin was Abineri's fourth and final appearance in the programme. He had previously played Van Lutyens in Fury From The Deep, General Carrington in The Ambassadors of Death, and Commander Railton in Death to the Daleks.
• The green dye proved difficult to remove, and the Swampie actors had to be ferried to a nearby USAF base to use their washing facilities.