Exar Kun was once a Jedi who served the Jedi, "Duh." He didn't like them because they were annoying hippies and they thought he was a nasty extremist. He eventually got sick of them and their rotten food, so he found a Sith holocron and began to scour the galaxy for power and better food.
Kun eventually settled on Yavin 4 and befriended the Massassi, despite their horrible culinary skills. After purging their food, decided to conquer the galaxy and serve himself better food than what he was eating on Yavin.
After a long dull and drawn out war, Kun's base was attacked. At the same time, Kun thought that he would try to see what would happen if he tried to eat his servants' souls used the force. He did that and then had such a huge purge that he was launched out of his body forever.
Behind the scenesEdit
In early character concept drafts Exar Kun who was a that point called Exar Koon was originally intended to be a black man. This was soon rejected because it was found to be racist against people with dark skin. The whole concept of the dark side being the root of all evil in the Star Wars universe was overlooked that occasion. The surname Koon was given to someone from a completely different race who looked disgusting and wasn't good enough to breathe our air to another character to cover up the deeds of the racist writers. Are you too beginning to see a pattern here?