Why Did Revan Turn to the Dark Side? Trayus and the Emperor

In Legends, Revan fell to the dark side in two steps. Sith teachings at the Trayus Academy on Malachor V pulled him in during the Mandalorian Wars, and then the Sith Emperor on Dromund Kaas seized his mind and Malak's and finished the job. Revan is Legends continuity, and in current canon his name survives as a Sith legend. (Knights of the Old Republic Campaign Guide, The Old Republic: Revan, Star Wars: The Rise of Skywalker: The Visual Dictionary)

Did the dark side start at Trayus Academy?#

Yes, according to the Knights of the Old Republic Campaign Guide (2008), which Wookieepedia follows. Revan and Malak were still fighting the Mandalorians when they reached Malachor V, where they found the Trayus Academy, an old Sith school. What Revan studied there started to draw him toward the dark side. (Knights of the Old Republic Campaign Guide, Wookieepedia)

He didn't renounce the Jedi ways at first. Even in the dark side's grip, he and Malak kept leading the Republic against the Mandalorians. The Campaign Guide also has Revan bring Malak into the Sith teachings there. (Knights of the Old Republic Campaign Guide, Knights of the Old Republic, Wookieepedia)

The original game tells it differently. In Knights of the Old Republic (2003), the Dantooine Jedi Council and Bastila Shan trace the fall to the ruins near the Enclave where the pair found a Star Map, and Vrook Lamar thinks they'd fallen before the Mandalorian Wars. Trayus and the Emperor came later, in the Campaign Guide and in Drew Karpyshyn's Revan novel (2011). (Knights of the Old Republic, Knights of the Old Republic Campaign Guide, The Old Republic: Revan)

Did the Sith Emperor turn them fully?#

Yes, in The Old Republic: Revan. Hunting the Sith who'd been pulling Mandalore's strings, the two Jedi tracked them to Dromund Kaas, the Empire's capital, and set out to kill the Emperor before he could invade the Republic. Wookieepedia's summary of the novel calls them proud and too sure of their own power, and the Emperor was waiting. (The Old Republic: Revan, Wookieepedia)

Rather than fight them, he seized their minds and completed their fall. Then he named them Darth Revan and Darth Malak and sent them ahead of his invasion to find the Star Forge. (The Old Republic: Revan)

His hold didn't last. They broke free of him some time before they boarded the Star Forge (Wookieepedia's Mandalorian Wars entry says not long after they left Dromund Kaas), but they'd taken his orders for their own wishes, and their minds stayed bent toward the dark side. (The Old Republic: Revan, Wookieepedia)

Why the fall stuck#

Partly because the Emperor's orders stayed in their heads as if they were their own, according to the Revan novel. Revan's beliefs as a Sith Lord pointed the same way. He held that dark side power was worth craving, he wrote off mercy and compassion as weaknesses, and he came to see loyalty as one too, because trusting an ally opened the door to betrayal. Those views come from Darth Bane: Path of Destruction, where Bane studies Revan's teachings. (The Old Republic: Revan, Darth Bane: Path of Destruction, Wookieepedia)

My read is that Trayus is where Revan started choosing the dark side, and Dromund Kaas is where the choice stopped being entirely his. Wookieepedia's Mandalorian Wars entry says that during the war, before Trayus, he and Malak had already slid into a win-at-any-price way of fighting, with moral shortcuts to match. To me that means the Emperor finished a slide that was already moving. I wouldn't call the Emperor the whole story. (Knights of the Old Republic, Wookieepedia)

Malak's end gives the other side of it. In Knights of the Old Republic, as Malak lies dying on the Star Forge, Revan says sorry for leading his old friend onto the dark path but reminds him that staying on it was Malak's own choice. Malak admits the Jedi Code might hold more truth than he'd ever given it credit for. (Knights of the Old Republic, Wookieepedia, Darth Malak)

When was Revan born, and where is he from?#

He was born around 3994 BBY. That year is worked out from The Old Republic: Revan, which makes him roughly forty at the time of its story. Knights of the Old Republic II says people believed he came from the Outer Rim Territories, so it's a belief rather than a confirmed fact. (Knights of the Old Republic II: The Sith Lords, The Old Republic: Revan)

As a young Jedi he trained with Alek, who took the name Malak in the Knights of the Old Republic comics, on Coruscant and at the Jedi Enclave on Dantooine. (Knights of the Old Republic, Jedi vs. Sith: The Essential Guide to the Force, Wookieepedia, Revan/Legends)

When did Revan live?#

The Legends dates run from his birth around 3994 BBY to his final death in 3637 BBY. These are the main dates the wiki gives:

• Around 3994 BBY: born, believed to be from the Outer Rim (Knights of the Old Republic II, The Old Republic: Revan).
• Before 3964 BBY: he and Alek reach the rank of Jedi Knight (Star Wars: Knights of the Old Republic Handbook).
• 3962 BBY: Supreme Chancellor Tol Cressa names him Supreme Commander (The Essential Guide to Warfare).
• 3960 BBY: at the Battle of Malachor V he defeats Mandalore the Ultimate.
• 3959 BBY: the Jedi Civil War begins with the raid on Foerost, per Star Wars: The Old Republic Encyclopedia (2012), which Wookieepedia's Jedi Civil War entry follows. The older New Essential Chronology (2005) put Foerost in 3958, and the Malak entry still uses that year.
• 3956 BBY: a redeemed Revan defeats Malak at the Battle of Rakata Prime, and the war ends (Knights of the Old Republic).
• Around 3642 BBY: the peace collapses, and Republic forces free Revan after three hundred years as the Emperor's captive. He dies at the Foundry soon after (Star Wars: The Old Republic).
• 3637 BBY: on Yavin 4 the dark and light halves of Revan merge and he dies a final death (Star Wars: The Old Republic: Shadow of Revan).

Read more#

Revan covers his whole Legends life. For the Sith side of the story, see the Sith, and for the Order he left behind, see the Jedi Order. For a fall to the dark side in the films, see why Anakin turned to the dark side.