Darth Malak is a Sith Lord of the Star Wars universe and the main antagonist of Star Wars: Knights of the Old Republic. His most visually distinctive traits are the tattoos atop his bald head and a prosthetic jaw; the result of a lightsaber duel with Darth Revan.
Darth Malak, was a human male born under the name of Alek Squinquargesimus. He reigned as the Dark Lord of the Sith during the Jedi Civil War. He was born on the planet Queli in the Outer Rim. He escaped Mandalorian invasion of his home world by fleeing to the Galactic Republic where he was trained in the ways of the force by the Jedi Order. Alek reached the rank of Jedi Knight. He met his closet friend Revan during this time and the two fought side by side in the Mandalorian Wars.
Darth Malak was the chosen identity of Alek Squinquargesimus, a famous Jedi who served during the war against the Mandalorians. He gained a somewhat notorious reputation for his headstrong beliefs and his recklessness especially when it came to combat. He was Revan's right hand man, the two having been friends since childhood.
After the Mandalorians attacked world after world under Republic control and their pleas for Jedi assistance were falling on deaf ears, Revan and Malak chose to act. They gave out patriotic speeches, proclaiming that as the peacekeepers of the galaxy, it was their duty to aid the republic in its time of need. They inspired the younger and more rebellious Jedis to their cause.
However, as the war progressed on, the death around them caused Malak on his path to the Dark Side. He relished in his new found powers and became extremely ruthless. Although, it is debatable whether Revan actually fell to the Dark Side first, he nevertheless guided Malak down that path. Together they converted the Jedi under their control and journeyed deep into the ancient ways of the Sith.
It was during one of these excursions on Dantooine that Revan and Malak found the ancient temple buried within the forbidden lands surrounding the Jedi enclave. There they learned of the Star Forge, an ancient Sith relic that fabled to be the ultimate weapon . After the defeat of Mandalore himself, the clans disbanded and the war was thought to be over.
However, Revan and Malak claimed to be hunting down the last remnants and disappeared off to the lonely outer rims. In reality, they were searching for the Star Forge, the sentient battle platform capable of extraordinary power. Together, they reemerged from the outer rims as Lords of the Sith. Revan, the stronger one of the two, took up the mantle of Master, while Malak assumed the role of the Apprentice. Using Revan's brilliance and Malak's ruthlessness, the duo conquered world after world.
The Jedi, in their desperate attempt to stop the fallen heroes, devised a plan with Bastila Shan to trap them. She, alongside a strike team, boarded Revan's flagship and confronted him. However Malak had plans of his own. In true Sith fashion, Malak fired on the ship, attacking Revan himself, and personally usurped the throne as the Dark Lord of the Sith.
Now firmly in control of the Sith, he resumed his attacks on the Republic and took an apprentice himself. Although he sorely lacked the military brilliance, and intelligence, that Revan demonstrated, he was nonetheless a capable leader and his enormous fleet was more than a match for the weakening Republic.
Fearful of his old master, Malak kidnapped the person closest to Revan, Bastila herself. Malak tortured her until she converted to the Sith. His attempts to turn Bastila against Revan ultimately failed as she was defeated by him, and thereby reveals her deep affection for the legendary Sith. The final confrontation took place on the Star Forge and although Malak fought with all the tenacity he could muster, drawing power from fallen Jedi held captive for his own use, he was defeated by Revan. He died a broken man, knowing in his heart that what he had done was wrong. His last words were, "In the end, I am nothing".
Some believe Revan reemerged as a Jedi and rejected the Dark Side while others maintain that Revan retook his place as Dark Lord of the Sith (for canon purposes it is said that the former is true - and that Revan indeed was male).