Warning: gigantic spoilers ahead for Episodes 12 and 13 of Star Wars Rebels Season 4, called "The Wolves and a Door" and "A World Between Worlds," respectively.
One of the longest-running mysteries of Star Wars Rebels was of what happened to Ahsoka Tano in the Season 2 finale after she faced off against Darth Vader. Given that Vader survived the encounter and nobody ever heard from Ahsoka after the episode, the logical conclusion was that Ahsoka perished in the battle... if not for one last shot that seemed to show Ahsoka descending down into the Sith temple on Malachor.
Ever since, fans have wondered if she did die and that was her Force spirit, if Ahsoka didn't die and she was just going down into the Sith temple for another reason, or if her ambiguous fate was showrunner Dave Filoni's way of saying goodbye to a major character who never appeared in the original trilogy. Well, "A World Between Worlds" resolved the mystery, and not in a way that anybody saw coming. As it turns out, Ahsoka did indeed survive the duel against Vader on Malachor, but it wasn't because she somehow managed to outfight him. Ezra saved her by reaching back in time and yanking her to safety before Vader could strike a killing blow. Ahsoka lives.
Yes, really. Ezra found a way to enter the Jedi temple on Lothal through a painting of the Mortis family, and he discovered himself in a world between worlds. The entrance via the painting wasn't just a different way into the temple Ezra had visited before; it was a portal to a pathway between all of time and space. Whoever controls the portal has access to a conduit that would allow influence on past, present, and future events. Given that the Emperor was dead set on gaining access himself, it was imperative that Ezra find a way to close the portal.
Unfortunately, Ezra didn't know any of this. Sabine got the lowdown on the portal from outside while Ezra explored the reality within. He could hear voices speaking, and he recognized some of them as Yoda and Obi-Wan. (Fans will have recognized quotes from everybody ranging from Qui-Gon to Jyn Erso to A New Hope-era Leia.) Ezra came across the owl-like convor that was always associated with Ahsoka on Rebels and recognized it as a creature with a connection to her. It was perched over a portal and seemed to want Ezra to do something with what was happening on the other side.
The other side of the portal gave Ezra a look into the past when Ahsoka was dueling Vader on Malachor. Although Ahsoka managed to sabotage the floor so it would crumble beneath them, Vader was on the verge of striking a killing blow... when Ezra reached right through the portal and yanked Ahsoka to safety in the world between worlds, alive but very confused.
Ezra was obviously thrilled to see her after spending a couple of years believing her gone, but Ahsoka refused to leave the Jedi temple with Ezra and join the fight on Lothal. Instead, she went back through the portal to Malachor and descended down into the Sith temple, just as we saw at the end of the Season 2 finale. Her return in "World Between Worlds" managed to change everything without contradicting continuity from the end of Season 2. Fortunately for Ezra (and viewers), Ahsoka did stick around long enough to give some important answers.
For one thing, the convor is a friend of Ahsoka's (and probably connected to the Daughter), which is why she was always around Ahsoka and helped Ezra find the correct portal to save her. For another thing, the gigantic Force-sensitive white wolf named "Dume" is not Kanan as a wolf, as some fans theorized. Instead, now that Kanan is part of the cosmic Force, his will could remain at work in the form of the wolf, even if he could not return himself.
Armed with this knowledge, Ezra decided that Kanan/Dume had sent him to the temple to prevent his death, and he raced to find the portal that would take him to Kanan's final moments. He did find the right portal, but Ahsoka managed to convince him not to reach through and save his master, as saving Kanan would have meant unleashing an explosion on Ezra and Co. and killing them. She beseeched Ezra to honor Kanan's sacrifice and let him go.
Since there may have been some of us out there who needed to have our hearts broken all over again about Kanan, "A World Between Worlds" gave us another angle on his death, let us see Ezra react again to watching Kanan die, and forced us to hear once more Hera's horrified scream as Kanan was consumed by flames. Ezra learned a valuable lesson about the importance of allowing and even embracing difficult moments, and Ahsoka helped him come to his conclusion.
Well, we finally know the truth of what happened to Ahsoka on Malachor back in Season 2! The big question now is what she'll be up to in the years between the end of Season 2 and the end of Season 4. She obviously doesn't come back to the rebellion in that span of time since a return would disrupt the timeline, but she could return to the action later on. That said, Ahsoka does not appear in the original film trilogy or any of the currently available canon material past the original trilogy era, so it's possible that she either never returns to the main action or she stays under the radar from the main players once she does come back. Only time will tell. Who knows? Maybe she'll pop up in the new Star Wars series or even the third installment of the sequel trilogy.
The final episodes of Star Wars Rebels air on Monday, March 5 on Disney XD starting at 8:30 p.m. ET. Be sure to tune in to find out how the stories of the Ghost crew end on the show. For the shows you can watch after Rebels comes to an end, take a look at our midseason TV premiere guide and 2018 Netflix premiere schedule. Don't forget to take a look at our rundown of ways Star Wars Rebels set up the events of Rogue One and our list of ways the latest episodes set the stage for the series finale.