10 Doctor Who Villains Who Ultimately Turned Good
2. The Master
Moriarty to the Doctor's Sherlock, the Master has been an on-and-off Doctor Who villain for nearly 50 years, and while the character delights in being evil most of the time, there have been a few flashes of good every now and then.
It's often forgotten that the Doctor and the Master are old friends: the pair grew up on Gallifrey together, and throughout their many meetings in the classic and revived eras, you can sense a strong friendship beneath all the death and destruction.
Hell, quite recently, the Master was even reformed into a full-on ally for the Doctor. At the end of Series 10 finale The Doctor Falls, Missy decides to stand with the Doctor after being moved by his pleas for help in an earlier scene, but before she can get to him, she's shot in the back and killed by a past version of herself.
The sad thing about this is that the Doctor never found out that Missy had decided to help him, and instead, the Master was resurrected as a bog-standard villain by Chris Chibnall, with that Series 10 character development being thrown in the bin.