Warning: MAJOR spoilers for The Rise Of Skywalker are ahed. Like, the as major as major gets.
Whether you wanted him to be redeemed or punched in the face, Ben Solo/Kylo Ren (Adam Driver) is easily one of the most memorable characters in the Star Wars prequels. Making fun of his villainous temper tantrums has been one of the high points in the sequel trilogy and mapping his sexual tension with Rey (Daisy Ridley) wasn't so bad either. That said, while what ultimately happens to Kylo Ren in Rise of Skywalker is bittersweet. Some fans will be devastated to see him die, but it's what needed to happen. He made amends, atoned for his previous atrocities, and helped save the day. That means it's time for his Star Wars story to end.
What Did Ben Solo Do To Rey?
Rey discovers in Rise of Skywalker that she has the ability to heal others using the Force, and uses that power to save Kylo Ren's life after she stabs him with his own lightsaber. Earlier in the movie, explains that Force healing requires transferring some of her own energy to the other being. So, when killing Emperor Palpatine (Ian McDiarmid) at the end of the film essentially kills her, Ben returns the favor and Force heals her back to life. The catch is that because she was dead, he has to transfer so much of his own energy to her that he has none left. So he dies, but not before the two share the kiss fans have been waiting for all trilogy. Even if you hated Kylo Ren the whole time, you have to admit that final moment is sweet. The Han Solo-esque grin that Ben flashes before dying doesn't hurt, either.
Why Does Ben Solo Disappear When He Dies?
Okay, here's where it gets complicated. It is a truth universally acknowledged in Star Wars that Jedis can become one with the Force and disappear... but not all of them have. Obi-Wan (Alec Guinness) certainly did when Darth Vader struck him down in A New Hope. Yoda (Frank Oz) did when he died in Return of the Jedi. Even Luke (Mark Hamill) vanished at the end of The Last Jedi. Qui-Gon Jinn (Liam Neeson) in Phantom Menace, however, did not — nor did any of the dozens of Jedi who were slaughtered in Revenge of the Sith. A scene that appeared in the script Episode III, and was later placed in the animated series The Clone Wars, explains that Qui-Gon Jinn (Liam Neeson) learned how to become one with the Force after death and taught that skill to Obi-Wan and Yoda as a Force Ghost. We can only presume that Luke passed this knowledge on to his padawans, which is how Ben managed to do so when he died.
It also seems that, if you are truly one with the Force, a Jedi can choose when to let their physical body go. That explains why Leia (Carrie Fisher) held on for her son, Ben, and then vanished simultaneously with him. Since Kylo Ren had become 100 percent Ben Solo by the end of Rise of Skywalker, and had some of Rey's energy coursing through him, he was connected enough to the Light Side of the Force in order to become one with it.
So, Why Isn't Ben Solo A Force Ghost?
Great question! It would have been nice to see him as a Force Ghost during the Resistance celebration, the way Yoda, Obi-Wan, and Anakin (Hayden Christensen) rolled up to party with the ewoks in Return of the Jedi. Maybe he felt it would be too awkward. Rey's kind of the only person who likes him at the party, and she was with her other friends, some of whom he definitely tried to kill. We've all been there.
But it does seem like he should have stood beside Luke and Leia when Rey visited Tatooine and saw their Force Ghosts together, but that spot isn't one that necessarily impacted Ben directly and Rey was burying their lightsabers. And perhaps Ben was too busy catching up with the other Skywalker to who turned back to the light, his grandfather Anakin. It stands to reason that if he was one with the Force enough to disappear, he definitely can be a Force Ghost. And after everything that happens in Rise of Skywalker, that's what counts.