Swampies were a race of green-skinned humanoids from the planet Delta Magna. When the humans colonised this planet they were forced onto the moon known as Delta III.
Without proper technology, the Swampies became primitives, operating as a tribe and performing sacrifices. Their technology was also very basic and so they relied on their environment during conflict.
Biology
Swampies were humanoid is shape but their skin was green in colour. Their hair was always braided and it was also green. As they could not rely on advanced technology, the Swampies were usually agile. (DW: The Power of Kroll)
Society
Swampies were greatly opposed to the presence of human's on Delta III. They intended to overthrow them by force and knew them as the "dry-foots".
The Swampies worshipped Kroll as a god and relied upon him to defeat their enemies. They performed dances of worship to praise him and offered sacrifices to appease him. Their methods of sacrifice varied greatly.
One such method involved an individual pretending to be Kroll by dressing up. Another involved the use of vines tied around the sacrifice. The vines would stretch in the sunlight becoming tighter until the victim's back was broken.
Swampies operated as a tribe with an appointed head who was also the religious leader. (DW: The Power of Kroll)
Technology
The Swampies had a low level of technology, which meant they were easily evicted by the Humans. They generally used spears and lived in grass huts. They made use of their environment, such as using vines to kill people in sacrifice. They were incapable of effectively using firearms as they had never encountered such weapons. (DW: The Power of Kroll)
History
Colonisation of Delta III
The Swampies were originally native to Delta Magna, but were moved to Delta III, one of the planet's moons by Human colonists, who they referred to as "dry foots". They had Human allies in the group, Sons of Earth. However the Sons' form of support proved ineffective. They predicted this with their sacred relic, actually the fifth segment of the Key to Time, and accepted this movement.
Worship of Kroll
The colonists also transplanted several giant squid to the moon for the Swampies to hunt. One of these ate the sacred relic and mutated into the "god", Kroll. When the Humans discovered that methane could be gathered on the moon they set up a refinery to gather it. They also gathered protein that was sent to Delta Magna. This angered the Swampies, who turned to a religious leader, Ranquin.
They were supplied with guns by Rohm-Dutt. They praised Kroll at night, intending to attack the dry foots the next day. They encountered a patrol in the swamp and fired. The guns misfired and Kroll appeared and attacked them.
They realised that Rohm-Dutt was working for the refinery, they took him prisoner. They also captured The Doctor and Romana. They devised an elaborate execution for them but they escaped. They pursued them but Kroll attacked them. This shook their belief in Kroll as their god.
The Swampies attacked the refinery as did Kroll. Kroll killed Ranquin and the Doctor restored the beast to his normal size. The refinery was closed and the Swampies freed from its oppression. (DW: The Power of Kroll)