Warning! SPOILERS for Obi-Wan Kenobi ahead.Star Wars still had many questions to answer by the end of the Skywalker Saga, and one of the biggest was how Obi-Wan Kenobi learned that Anakin Skywalker survived their battle in Mustafar. Star Wars Legends had an answer, but after Disney acquired Star Wars and made Legends non-canon the question was left unanswered again for over a decade. Obi-Wan left Anakin for dead after their duel on Mustafar, but when they met again on the Death Star 19 years later the aging Jedi master knew who Darth Vader was under the helmet. Thankfully, the Disney+ Obi-Wan Kenobi series refilled this gap in their character arcs, so here's how Obi-Wan found out Anakin didn't die in Star Wars: Episode III - Revenge Of The Sith.
Back in 1977, George Lucas changed the sci-fi genre forever (and the film industry as well) with the film now known as Star Wars: A New Hope, which introduced audiences around the world to a whole new universe with strange planets, spaceships, its own political system, and a lot of unforgettable characters. The film was followed by Star Wars: The Empire Strikes Back and Star Wars: Return of the Jedi, forming the “original trilogy”. In order to expand this universe and explore the backstories of some of its characters (mainly Darth Vader), a prequel trilogy was released between 1999 and 2005. Though these films helped fans understand Darth Vader/Anakin Skywalker’s life, they also left even more questions that haven’t really been answered, among those how Obi-Wan Kenobi learned that Anakin was still alive.
After defeating him in Mustafar, Kenobi believed Anakin didn’t survive, until they reunited in Star Wars: A New Hope, where Vader killed his former master. But when and how did Kenobi learn that his apprentice was alive? This question was finally answered in the Obi-Wan Kenobi Disney+ series, but for many decades there was a totally different explanation. Here's how Obi-Wan learns about becoming Darth Vader after surviving their duel on Mustafar, both in the now de-canonized Star Wars Legends Expanded Universe and the Disney Star Wars canon.
How Obi-Wan Learned Anakin Survived In Star Wars Legends
All non-film material produced prior to April 2014, except The Clone Wars, is considered non-canon and is filed under the name of Star Wars Legends. This side of the Star Wars universe once offered an explanation on where, when, and how Obi-Wan Kenobi learned that his former Jedi apprentice survived their duel in Mustafar and was now a proper Sith lord. In the novel Dark Lord: The Rise of Darth Vader, written by James Luceno, Obi-Wan Kenobi was at a cantina when he heard the news of Darth Vader’s victory at the Battle of Kashyyyk. In the material around the film from the Legends timeline, it's established that by the end of Star Wars: Episode III - Revenge of the Sith, Kenobi was one of the characters who knew Anakin’s Sith name was Darth Vader. However, what he didn’t know was that he was still alive after Mustafar.
This moment comes a few months after Obi-Wan arrives on Tatooine. Upon learning from the HoloNet (the Star Wars version of the Internet and TV) that a man sharing his former apprentices Sith title was slaughtering Wookies, Obi-Wan consulted with the Force Ghost of his own master, Qui-Gon Jinn. Qui-Gon confirms that the Vader of Kashyyyk is indeed the same anger-filled former Jedi that Obi-Wan left for dead on Mustafar. In the Legends timeline, Obi-Wan remained in hiding on Tatooine until the events of A New Hope. Obi-Wan and Darth Vader dueled several times — their first duel was in Episode III and their last 19 years later in Episode IV.
Reva The Third Sister Told Obi-Wan Kenobi That Anakin Lives
The canonical moment in which Obi-Wan finds out Anakin survived comes in 2022's Obi-Wan Kenobi Disney+ series. It's also much more satisfactory than the Legends explanation and is treated as the turning point for both characters that it rightfully should be. Set 10 years after the events of Episode III, Obi-Wan Kenobi finds the titular Jedi hiding on Tatooine. His mental state is fractured, broken by many events that transpired during and after the Clone Wars, not least of which are Order 66, the massacre at the Jedi temple, and having to kill his own Padawan. McGregor's Kenobi has PTSD, and the guilt he harbors at failing Anakin (both by killing him and letting him fall to the Dark Side in the first place) is a significant causal factor.
In the official Disney Star Wars timeline, Obi-Wan doesn't know Anakin Skywalker took on the name Darth Vader. This isn't breaking any established canon either, since he's never referred to as Vader in front of Obi-Wan during Revenge of the Sith. He first hears the name Darth Vader on Tatooine and knows him only by reputation as a fearsome Jedi hunter. Obi-Wan's self-imposed exile is interrupted when the Inquisitorius, and in particular Reva the Third Sister (Moses Ingram), kidnaps the child Princess Leia knowing this will lure Kenobi out of hiding. In Episode 2 of Obi-Wan Kenobi, their plan works, and he leaves Tatooine for Daiyu. It's here, when confronting Reva, he learns that Anakin didn't die on Mustafar. Reva knows Darth Vader's true identity, and she uses this fact to taunt the distraught Obi-Wan. That's the moment in Star Wars when Obi-Wan first learns that he didn't end Anakin Skywalker's life. However, by the time they have their second duel in the Obi-Wan Kenobi finale, it's clear the student he once taught is so lost to the Dark Side he might as well have.