Timelord are the race of humans who live on the planet of Gallifrey. One Timelord The Doctor travels through time and space defeating foes of his such as Daleks and the Cybermen. The Doctor and his nemesisThe Master were thought to be the last Timelords after a battle between The Timelords and Daleks allegedly destroyed the Gallifrey home world, however, it turned out the Doctor put Gallifrey into a time stream to be returned later in the future. The Timelords are led by Rassilon, a Timelord who stays on Gallifrey.
Timelords are able to regenerate when their life has all but gone. After twelve regenerations per cycle, they can get a new cycle of regeneration. The Master had used up all his regenerations but also was granted more. In the 2014 series, the Master returned as a female known as the Mistress.