Darth Malak was a Human male born on Quelii who took the mantle of Dark Lord of the Sith during the Jedi Civil War. Before taking the name Malak, Alek Squinquargesimus, nicknamed Squint, was a famed Jedi Knight and military commander. During the Mandalorian Wars, Squinquargesimus gained a reputation as a headstrong warrior who would recklessly charge into danger. He befriended the Jedi Padawan Zayne Carrick, whom he assisted in defeating the Jedi Covenant shortly before taking the name "Malak." He eventually drew closer and closer to the dark side, ultimately being seduced by Sith teachings imparted to him by his closest friend, Revan. After the final battle of the Mandalorian Wars at the Sith planet Malachor V, the two twisted the allegiance of the Revanchists and the Republic forces under their command, building the foundations of what would eventually become a new Sith Empire.
In his role as Revan's chosen apprentice, Darth Malak helped his Master track down the Star Maps, devices that led to the Star Forge, an ancient superweapon built by the Rakata. A year after Revan and Malak disappeared from known Republic space into the Unknown Regions, they returned and declared war on the Republic, determined to end the "tyranny" of the Jedi Order. At one point under Darth Revan's tutelage, Malak's entire jaw was removed by a lightsaber strike from Revan himself, forcing Malak to wear a large metal prosthesis. After the Jedi dispatched a strike team to capture Revan and Malak, the latter betrayed his Master, ordering the guns of his flagship to fire on Revan's vessel. Convinced that his Master had died, Malak usurped Revan's mantle of Dark Lord and ruled the Sith unchallenged, brutally conquering territory after territory. He even took an apprentice of his own, a former Jedi named Darth Bandon.
It would not be long until Malak was proven wrong about his belief that Revan was dead. The next year, Malak intercepted the Jedi Knight Bastila Shan and an amnesiac Revan, whose identity as the Dark Lord had been replaced with an identity that was loyal to the Republic by the Jedi Council. After Malak told Revan of his former identity as the Dark Lord, Malak and Revan fought each other, but Shan allowed herself to be captured by Malak so that Revan and his companions could escape. Malak corrupted Shan, whom he had once considered a threat. She eventually became his apprentice, replacing Darth Bandon, whom Revan and his companions had previously killed. Now assisted by Shan's battle meditation, Malak considered his Sith Empire to be invincible. When the Republic fleet attacked the Star Forge above Rakata Prime, a redeemed Revan boarded the ancient space station and confronted Malak in a lightsaber duel that resulted in the Dark Lord's defeat. With that, Malak's reign as the Dark Lord ended, and the Republic was victorious.
"Darth Malak is the self-proclaimed Dark Lord of the Sith and former apprentice to Darth Revan. Revan and Malak started the Jedi Civil War 4000 years before the rise of the Empire. Half way through the war, a Jedi Strike team was sent to board Revan's flag ship. Bastila Shan leading the team, the Jedi had Revan cornered when Malak all of a sudden fired on Revan's ship seriously injuring him and wiped his memory . Malak assumed the title and continued the war. Malak almost won, but Revan regained his lost memory and defeated the trechorus villain. Malak makes a second appearence in Knights of the Old Republic 2 as a memory ghost during a challenge the main character takes."