Cassian Palpatine's time training on Korriban caused him to run into a group of Dark Jedi in 8 BBY being trained in the Korriban Sith Academy which had been reoccupied by a sizeable number of Darksiders who had remained hidden on the world, Cassian at one point defeated the strongest members of this Academy and allowed them to live instead of killing them as a true servant of the Rule of Two would have by command by Darth Sidious.