Karfel was a planet inhabited by near-Humans known as Karfelons. It had diplomatic relationships with the planet of the Bandrils. A council, located in the Citadel, governed life on Karfel.
The Doctor first visited the planet with Jo Grant (DW: Timelash) and Mike Yates. Originally they meant to simply have dinner there but spent a much longer time. (MA: Speed of Flight)
During this visit, a local artist painted a mural of himself in the Citadel. Jo gave a locket containing a photo of herself to the father of a Karfelon named Katz. The Doctor reported to the local authorities the "unethical" experiments of a scientist named Megelen on a local life form called Morloxes.
Trapped by a kontron tunnel, the Doctor's TARDIS landed on Karfel once again. By this time, Megelen, as the Borad, now ruled the planet as a dictator with the aid of androids. The Borad created the kontron tunnel, which he called the Timelash and used it as a means to exile his enemies.
With his companion, Peri and a young H.G. Wells, the Doctor freed Karfel of the Borad and averted a war with the Bandrils. (DW: Timelash)