Darth Hashashin

Kazahk Sturn, better known to the galaxy as Darth Hashashin, was an ex-Jedi who came to the attention of Darth Vader in 19 BBY during the Great Jedi Purge. Vader sensed that he held much anger towards the Empire. Vader managed to turn this into usefulness by telling him that the Chancellor had ordered the attack, thus embittering Sturn forever. Sturn was Vader's true assassin for many more years, even being present on the Death Star in 2 BBY when Galen Marek was killed.