Darth Sion, along with Darth Nihilus and Darth Traya, is one of the title characters in Star Wars Knights of the Old Republic II: The Sith Lords. His body consists of bits and pieces held together by sheer force of will and the power of hatred embodied by the dark side.

When the Sith Order on Korriban turned on themselves after Malak's death and Revan's disappearance, Sion was apparently one of the Sith Lords that have escaped to the unknown regions in the galaxy. It seemed he had escaped to Malachor V, where he was apprenticed by Darth Traya, a former teacher of Darth Revan.

Sion was a very uniquely powerful individual. He had learned the way of pain. He grew stronger in the Darkside of the force, by inflicting pain, torment, and death on individuals with who he stalked. He also fed upon his own pain, for power and a supernatural ability to survive. A master with a lightsaber, and perhaps the most famous, or infamous Assassin of the Sith. Is known to be responsible for the death of countless jedi, during his reign as a Sith Lord.

Darth Sion, along with fellow Sith Lord Darth Nihilus, was a former apprentice of Traya, before he and Nihilus cast her out of the Sith Order and stripped her of her powers. 3,951 years BBY, he was killed by the Exile who had served Darth Revan during the Mandalorian Wars in the Trayus Core, the heart of the Trayus Academy on the ancient Sith world of Malachor V.

Having lived so long knowing nothing but hatred, he was glad to leave that evil place at last.

Like most other Sith Lords whose names begin with Darth, Sion's name suggests another word: scion, meaning heir. In this case, heir to his master, Traya, and the legacy of the Sith

Quotes "I can feel you my master, faint, weak. Why have you returned, is it vengeance you seek, for if that is so then you will fail."

"Have you come here to die like the jedi before you, this place is a graveyard for your kind."

"Long have I waited for the last of the jedi to fall at my feet."

"You are a wretched thing, of weakness and fear."

"I can die a hundred times exile, and each time I shall rise, as strong as before."

"Kreia, she will try to break you, and when she does you will fall, and if you do, you will die."

"As long as the dark side flows through the cracks of my flesh, I cannot be killed."

"I will not fall, I cannot die."