Star Wars: Enemy of the Republic - Dark Side
Mastema is a Force Demon, an evil entity of pure energy and utter malevolent darkness that has existed for more than 25,000 years. It’s mastery of the deepest secrets of the Dark Side of the Force borders on being magical, and it can create almost any effect it wishes. Despite this, it was captured millennia ago in a crystalline prison and left on the world of Kaal by some long-forgotten enemy. It was found on that world by Ellor Novan, and Mastema attempted to use Ellor to escape it’s prison. It failed, but the mere act of brushing against Ellor’s mind corrupted him fully to the Dark Side, and he slew his Clone Trooper detachment and spent the next several years on trying to figure out some way of tapping Mastema’s power for his own. He eventually found Rakatan artifacts that would allow him to drain Mastema’s limitless power, at the cost of his own health. Despite the power that he drew from the demon, Ellor was defeated by his former students, and Mastema was freed back into the galaxy.