Disney+'s Star Wars: Episode III - Revenge of the Sith, charting what happened to Obi-Wan while he was living in exile on Tatooine.
Of course, despite it being accepted canon, it's unlikely that Obi-Wan will stay on Tatooine for the duration of the show, since making an entire series of him hiding out in the Jundland Wastes may not make the most exciting of spectacles. The Obi-Wan Kenobi show cast fits with this, as there are so far 10 actors confirmed for the show, including the likes of Kumail Nanjiani, Sung Kang, Indira Varma, and Moses Ingram. The extensive roster of newcomers suggests new locales and characters, but there will be plenty of familiarity for fans too.
Unsurprisingly, this will be a Star Wars show that has big connections to both what comes before it in the timeline and what comes afterwards. Obi-Wan is making some big additions to canon and changes to what's known, and that will factor into its returning actors and characters as well.
Ewan McGregor as Obi-Wan Kenobi
The star of the show, of course, is Obi-Wan Kenobi, who first appeared to Star Wars viewers back in 1977 played by Sir Alec Guinness. Back then, Kenobi was an old hermit who had been living in exile as Ben Kenobi for several years, before he was struck down by Darth Vader, but the Star Wars prequels were able to show him off in his prime. Played by Ewan McGregor across all three movies in that trilogy, Kenobi was one of the highlights of the series, adding an extra level of wit and charm to the character that went well with the gravitas of Guinness.
McGregor was perfect casting, so it's great that the actor - also known for his roles in the likes of Trainspotting and more recently Birds of Prey - is finally able to return to the role. With the timeline falling almost exactly at the halfway point between Revenge of the Sith and A New Hope, then Obi-Wan Kenobi will perfectly be able to show the transition from the hero of the Jedi Order to the wizened old man of the original trilogy (and perhaps explain how he aged so much as well). Having defeated Anakin Skywalker but with the Jedi being slaughtered due to Order 66, Obi-Wan's time on Tatooine was to designed to not only help him stay safe but also to keep watch over Luke Skywalker, so it'll be fascinating to see just what prompts him to leave the desert planet.
Hayden Christensen as Darth Vader
As well as Ewan McGregor as Obi-Wan Kenobi, as the other major returning Star Wars character is Darth Vader, who will once more be played by Star Wars: Episode II - Attack of the Clones and Star Wars: Episode III - Revenge of the Sith, getting to play the character's dark side turn that culminated with him becoming Darth Vader. Christensen's portrayal wasn't well-received by fans at the time but, as with the prequel trilogy as a whole, time has been kind to the actor and fans have not only forgiven him, but generally have a lot of goodwill to the actor. That unfortunately didn't lead to an appearance in the Star Wars sequel trilogy, and the actor hasn't had many other major roles since (2008's Jumper is as big as it gets), but Christensen is finally getting his comeback opportunity thanks to Obi-Wan.
The potential for Vader's role in Obi-Wan is huge, especially as Christensen is seemingly getting second billing behind McGregor. That means he should have a big part to play, and that makes sense given there has been a promise of a rematch between Obi-Wan and Vader. The original Star Wars suggested it was the first time they had met in a long time, and Revenge of the Sith seemingly showed that. This will add a new, unexpected and so far unknown battle between the pair, and one where they might be the most evenly matched they've been. The specifics of Vader's role aren't known yet, but since he will be facing off with Obi-Wan, then he could be involved in whatever makes Kenobi leave Tatooine, with the pair possibly after the same thing that puts them on a collision course.
Joel Edgerton as Owen Lars
Another Star Wars prequels actor back for Obi-Wan Kenobi is Joel Edgerton (King Arthur, The Great Gatsby), who will presumably be playing Tatooine.
Bonnie Piesse as Beru Lars
With Owen Lars returning, then it makes sense that Beru Whitesun Lars would be as well, with Bonnie Piesse - who also appeared in Attack of the Clones and Revenge of the Sith - set to reprise her role. While Beru meets the same grim fate as Owen, she hasn't been fleshed out quite as much in canon, although she does serve as a counterpoint to Owen in the upbringing of Luke, being kinder and more ive of her adopted son against Owen's overprotectiveness and expectations. By bringing the character back, though, there's a chance to give her an even greater role, and perhaps reveal more interactions with Obi-Wan Kenobi, which can deepen the character and give her eventual death more weight.
With Obi-Wan Kenobi's place in the Star Wars timeline, then it is possible there may be other characters who appear as well. The appearances of Owen and Beru Lars, in particular, raises the possibility that a young Luke Skywalker could appear, since he will be with them at this point, but that remains to be seen.