The Grand Inquisitor
Formerly a member of the Jedi Order’s Temple Guard, the Grand Inquisitor turned to the Dark Side after the rise of the Empire. Under the tutelage of Darth Vader, he began training similarly Force-sensitive beings to hunt Jedi for Vader and the Emperor. He was first introduced in the animated show Star Wars Rebels, hunting down Jedis Kanan Jarrus and Ezra Bridger, before ultimately falling to Jarrus.
This, however, takes place before that. Obviously.
