Darth Revan

Revan, renowned as "The Revanchist" and dreaded as the Sith Lord Darth Revan, was an eminent Jedi Knight turned conquering Dark Lord of the Sith until, stripped of his true persona, he returned to the crumbling Jedi Order and helped defeat the Sith Empire he had established.

A human male, and acknowledged as a very gifted and powerful Force-sensitive pupil, he was trained as a Padawan by Kreia and a number of other Jedi Masters, both on Coruscant and at the Jedi Enclave on Dantooine.

He was voiced by Rino Romano in Knights of the Old Republic (2003) and by Jeff Bennet in The Old Republic (2011).

History
Who will become the Reknown Jedi Revan began as a Jedi Padawan who was said to have incredible potential from a very young age.rumored that was born on the Outer Rim.

as a young padawan he had a deep thirst for knownledge and great force power that didn't get unobserved by the eyes of the elder members of the Jedi order,who thinked of Revan to be a future champion of the order.but Revan wanted to learn everything from his masters and how to exploit it to his advantage,like Kreia's manipulation techniques.

Befriending fellow Padawan Malak, Revan very early showed a natural charisma and an ability to sway others to his way of thinking. So it was that when the Mandalorian Wars broke out and the Jedi Council did nothing, Revan vowed to fight the Mandalorians anyway, and rallied numerous Jedi to his cause.

Unfortunately, Revan's experiences during the wars rapidly began to turn him into a colder, ruthless, and more callous individual who soon came to believe that the ends justified the means. By the end of the war, Revan's manners of execution changed dramatically.

Before the battle of Malachor V took place,Revan visited the planet,when he landed he felt a strong dark side energy trying to overwhelm him,but he managed to control that energy and gain massive power,after that he found the Trayus Academy,a old Sith empire outpost,where he discovered that the "true" Sith that existed during the great hyperspace war were not destroyed but still active on the verge of Space and were possible responsible for the Mandalorian Wars.Realizing that the Republic was too weak to stand against them,Revan planned once the mandalorians were beaten to raise an army and conquer the Republic in order to protect the galaxy from them.

After ruthlessly eliminating the Mandalorian fleet above Malachor V and personally executing Mandalore the Ultimate, Revan took his remaining followers, including his friend Alek (now known as Malak) and disappeared declaring to the Republic that he took 1\3 of the Republic Fleet to find the last remaining Mandalorian ships,but he traveled to Dantooine in secret where he searched in the jedi archives and ventured into the ancient dark side rakatan ruins,there Revan spoke to the Overseer,the last droid in the ruin left intact,and told him about the Star Forge and that the Star Map holds the answer,but once Revan found the Star Map,it was uncomplete,so Revan and Malak traveled to the worlds marked by the Star Map,and once they found all four,they traveled to Lehon,where Revan assumed the title of the Dark Lord of the Sith,leaving Malak the rank of apprentice.

Knights of the Old Republic
Using the Star Forge to create limitless fleets, Revan waged war against the Republic and the Jedi Order. At first the crusade went well,restablishing old sith fortifications such as Malachor,Korriban and Dxun,his sith assassins flowed from Malachor V hunting or converting Jedi to the dark side.

Using cunning than brute strength,Darth Revan conquered worlds but kept the planetary installations and governments intact to create less damage possible.his tactical and strategical abilities combined with the defecting Republic officers experience made his empire nearly invincible,in matter of two years conquering 1\3 of known space,his reputation as saviour of the galaxy from the Mandalorians inspired many idealists to join the sith empire,believing them to be the heroes instead of the Jedi Council who did nothing.

However this did not last long. Malak, desiring Revan's power for himself and tired of being subservient to his old friend, betrayed him, ordering his ships to fire on his bridge while he was distracted fighting a Jedi strike team sent to capture him,if it wasn't for Malak,the Jedi Strike team would have been killed.

Believed dead by all, Revan in fact survived, and was revived by the Jedi. Left amnesiac from the events, Revan was given a new identity with which the Jedi hoped to use Revan to finally destroy the Star Forge and stop Malak for good. Though Revan eventually recovered his memories, by that point he had returned to the Light Side and no longer wished to return to the life of a Sith Lord, instead standing against his old apprentice and also forgiving Bastila (who he had come to love) for her part in re-writing his memories.

Dark Side Ending
In the Dark Side Ending however,Revan accepted Bastila's offer on the Temple of the ancients to reclaim his lost identity,striking down Jolee and Juhani,their blood on the ruins signing the return of the Dark Lord

Once at the Ebon Hawk Darth Revan made Carth flee and manipulated Zaalbar into killing Mission Vao,after departing from the Unknown World,Darth Revan planned with Bastila to use the Republic to distract Malak and destroying them afterwards and fooled Vandar.

when Darth Revan arrived on the Star Forge,he made his way with Bastila to the command center,where Bastila used her battle meditation to turn the tide of the battle in favour of the Sith fleet.

once he managed to survive the Star Forge's automated defenses,Darth Revan arrived on the observation platform,where the two battled and Revan slew Malak,shortly after the Republic Fleet is destroyed,leaving now the Core Worlds defenseless. once Revan returned to Lehon,he was finally declared Dark Lord again.

The Old Republic: Revan
For a time Revan was able to retire and live with his wife Bastila Shan and their new son, before lingering nightmares of a world he visited during his fall to the Dark Side drove him to seek out the source.

The Old Republic
After 3 centuries of being imprisoned by Darth Vitiate, Revan descended into insanity and decided that the best way to stop the Sith for good would be to commit genocide against them, in the process succumbing to the Dark Side again. Revan was later freed by a Jedi strike team led by Barsen'thor, the group not aware of Revan's madness. There was now nothing to restrain Lord Vitiate anymore. Revan then joined the Jedi again in their struggle against Darth Vitiate and the Sith Empire.

Revan's second disappearance
"And in the end, as the darkness takes me, I am nothing. Now I know how you felt, old friend."

- Revan repeating Malak's last words before disappearing.

However, Revan was defeated by a group of Sith and Bounty Hunters sent to stop him, at which point he disappeared in a flash of light after repeating Darth Malak's final words, stating that now he knew how he felt then.

The Order of Revan
After his defeat at The Foundry Revan remembered hearing about an imperial cult that revered him and decided to seek them out. When he  found them and became their leader he began planning to destroy both the Empire and the Republic by creating an army using Rakata technology and recruiting high ranking members of both factions in order to undermine them.

Trivia

 * He never officially speaks in Knights of the Old Republic though Rino Romano does provide some hard to hear taunts.
 * Revan was seen as a role model by later Sith Lord Darth Bane despite his being redeemed, and Bane even traveled to Lehon to seek out Revan's Sith Holocron. It was from that holocron that Darth Bane first learned about the Thought Bomb that he later used to wipe out the Brotherhood of Darkness and the Jedi they were fighting on Russan.
 * Revan and Bane were both meant to appear in the third season of Star Wars the Clone Wars as "advisors" to the Son, goading him to embrace the Dark Side more and more. The scene was cut due to conflicting with George Lucas' ideas of the Force.
 * Revan's ideals seem to have been changed in SW:TOR Revan novel,where Revan was described to have fallen to the dark side because he was mind controlled,while in SW:KOTOR 2:TSL it was hinted that he did pretended to be evil for choice to save the galaxy again from the "true" sith and considered the dark and light side as mere tools.
 * The true Sith in SW:KOTOR 2 were described as the embodiment of pure dark side followers capable of terrible force powers as weapons and so powerful that couldn't be stopped by normal means,while the empire shown in TOR resembles much the movies and followed a usual Sith ranking,with the Emperor Vitiate as Palpatine,The Empire Troops as Stormtroopers and power that can be like or less the Sith of SW:KOTOR