a new version of Force Heal, with Rey mastering a power that allowed her to transfer her life energy to another. She first used on a desert snake, and then again to save Kylo Ren from death after their fateful lightsaber duel on the wreckage of the Second Death Star.
There seems to be a reason this power is rare; because it is not associated directly with either light or dark. Outside of Rey, it's only been seen in Children like Baby Yoda, who isn't yet explicitly light or dark in The Mandalorian; meanwhile Rey had been studying ancient Jedi texts that seem to have dated to before the Jedi became dedicated solely to the light side of the Force, explaining why she learned it. Because this Force Heal power has only been seen a handful of times, viewers are still figuring out just how it works.
Lucasfilm has recently published a biography of the Skywalker family by Kristin Baver, Skywalker: A Family At War, and it confirms there is a spiritual dimension to this new Force Heal - and that it played a part in Kylo Ren's redemption. "Healing through the Force is a peculiar thing," the book observes. "Rey transferred her own Force energy to the wounded man at her feet; however, the interaction did more than merely mend a gaping wound. Burned flesh and damaged organs were made whole again, and even the scar on his face disappeared. For the first time in more than a decade, Ben Solo's mind cleared."
There is a sense in which Kylo Ren never truly fell to the dark side, but instead was imprisoned by it. This is hinted at in Star Wars: The Rise of Skywalker, when he urged Rey to "surrender" to the darkness, echoing his own experience; tie-ins have since emphasized the point, with Charles Soule's The Rise of Kylo Ren revealing the lengths Palpatine went to in order to trap Ben Solo at a young age. His mind had always been clouded by the darkness of Palpatine's presence, and when Ben learned he was the grandson of Darth Vader he felt unable to escape his destiny. But Rey's Force Heal had a transformative effect on Ben's mind, freeing him from the Emperor's influence, granting him clarity of thought for longer than Ben could possibly .
This fits well with Star Wars lore, for indeed attentive viewers had long noted Force Heal appeared to have a redemptive aspect to it. Baby Yoda used it on Greef Karga, and immediately afterwards he began to demonstrate a conscience for the first time in his life; the desert serpent slithered away, losing its aggression; and Kylo Ren was redeemed immediately after being healed by Rey. Still, it's fascinating to have that spiritual dimension of the power officially confirmed.
It's important to understand this was only part of the process, of course. Princess Leia died reaching out to her son in the Force, and Ben realized his mother had expended the last of her energy not on leading the Resistance but on reaching him. The combination of Leia's love and Rey's sacrificial act, her willingness to give her own life energy to save Kylo Ren from death, brought him to a place of redemption at last. And so Kylo Ren became Ben Solo once again, tossing his crimson lightsaber into the waters of Kef Bir, finally becoming a hero in the Star Wars saga.
