Darth Nihilus was created by Obsidian Entertainment as one of the primary antagonists for the 2005 Xbox and PC video game Star Wars: Knights of the Old Republic II: The Sith Lords. His story was later elaborated upon in a comic, Unseen, Unheard, featured in Star Wars Tales 24.
Darth Nihilus was a Human male who reigned as a Dark Lord of the Sith during the era of strife following the Jedi Civil War. Before becoming a Sith Lord, he lost everything during the Galactic Republic's war against the Mandalorian Neo-Crusaders.
He was a figure of the shadows. He always craved greater power. However, unlike most Sith Lords, he cared very little for the Sith as an organization. Nihilus saw death as the sole purpose of life, and power as the means to achieve it. He was cautious, as his actions during the campaign against the Jedi showed, and was known as an aggressive, dominant figure who would not abide a threat to his power. After he was forced to shed his physical being, he ceased to feel fear and other emotions; he became an entity of pure intent. Nonetheless, Nihilus was still human enough to have some feelings, as his bond with Marr persisted until their confrontation on the Ravager. She was his only apprentice, and her betrayal was met with much anger. Darth Nihilus wielded a self-built lightsaber containing a red crystal.