The Borad
The Karfelon known as The Borad began life as a scientist of the planet Karfel named Megelen, who was encountered in an as-yet unrecorded adventure by the Doctor. (The Karfelons used Borad a title, like President, rather than a name, however, when Megelen took power he referred to himself only by his title.)
During his first visit, the Doctor exposed Megelen to the ruling Council for unethical experiments on Morloxes, large reptiles indigenous to Karfel, and the chemical Mustakozene-80, which has the ability to fuse together different tissue as one creature.
After the Doctor left Karfel, Megelen was apparently able to continue his experiments, but was accidentally fused with one of the Morloxes via Mustakozene-80, becoming half Morlox and half Karfelon. He believed that his intelligence and longlevity had increased.
Megelen also experimented with cloning and creating at least one duplicate of himself after the accident. He was able to install himself as the sadistic and despotic ruler of Karfel under the name of the Borad. He never reveals himself in person, only via security monitors which reveal him to be a dignified old man. Mirrors were banned. Fear was enforced rigidly through the policing of androids; and all rebels are dealt with either by summary execution or despatch and death via the Timelash to 1179 Scotland, near Loch Ness.
Under the Borad’s rule, the Karfelon people became disillusioned, rebellious and miserable, and relations break down with their former allies, the Bandrils, who threatened war after the Borad rescinds the grain supply treaty which underpinned the relationship between the two civilizations.
A war with the Bandrils that would result in their use of bendalypse warheads which will wipe out all the Karfelons but leave the Morloxes and the Borad alive,
The Borad had started to re-create the Mustakozene-80 experiment using the Doctor's companion Peri and a morlox to create a second hybrid, mate with her and re-populate Karfel with their off-spring.
The Doctor was ultimately able to defeat the Borad when Megelen is made unbalanced by the image of himself in a boarded-up mirror, revealing the reason he hid himself away, and in this state is thrown into the Timelash by the Doctor. It is unknown whether he survived the journey, although the Doctor apparently thought he would and speculated that the Borad will become the Loch Ness Monster. (DW: Timelash)
The Borad, however, died shortly after his arrival at Loch Ness. (EDA: The Taking of Planet 5)
