The people most responsible for Darth Vader's eventual redemption are not Luke Skywalker or Emperor Palpatine, but Padmé and her handmaiden Sabé. After the shocking events of Star Wars Episode V: The Empire Strikes Back, Lord Vader starts to dwell on the past. He takes a trip across the galaxy with a forensics droid to find out what happened to his dearest Padmé. On Naboo, he finds a familiar face, none other than Sabé, his lost love's handmaiden and doppelgänger! The shock of his past leads Vader to sink into the depths of misery before letting Padmé and Sabé change his heart.
Star Wars: Darth Vader — Dark Heart of the Sith by Greg Pak and Raffaele Ienco chronicles Vader's experiences immediately after his confrontation with Luke. His fixation with turning his son to the dark side leads Vader to wonder who turned his son so forcefully against him. Haunted by memories of Obi-Wan "corrupting" his beloved Padmé, he takes off on a journey of revenge. Although he is to blame for killing Padmé and making an enemy of Luke, he craves vengeance. A short way into his journey, he runs into an old friend: Sabé, Padmé's decoy. Possessed by the ghosts of their shared past, Anakin and Sabé set out together to unravel the story of Queen Amidala's mysterious death and the birth of her son.
This journey across Naboo brings a full range of negative emotions to the surface for Vader. Frequent flashbacks to the pain he inflicted on Padmé fill him with guilt. Constant attacks from the late Queen's loyal followers, "The Amidalans," turn him to rage. However, the longing triggered by seeing Padmé's face again racks the Dark Lord's soul with grief. It becomes clear that Vader's anguish over the death of his wife is not a stable foundation for his hatred or his power in the dark side. Throughout the story, while Vader does display uncharacteristic mercy towards Sabé, he is still Vader for the time being. In the end, he lures Sabé and the rest of the Amidalans into a trap and kills them all.
While the fire of Vader's rage burns bright in that scene, the effect of his journey with Sabé sets in over time. Before dying, she and the Sith Lord discover the planet where Padmé's life ended. There, he learns her final words: "Obi-Wan... there's still good in him... I know... I know... there's... still..." This revelation has a profound impact on Vader's destiny. The Emperor himself calls out his apprentice, saying that where there was once power, now there is grief. Despite his best efforts to re-instill hatred in Vader's heart, Anakin prevails in Return of the Jedi.
Without Padmé's decoy to show Vader who he had become, he may have never turned back to the light. To the Dark Lord of the Sith, it was never about the Empire, or Luke, or his master. It was about Padmé. His experiences with Sabé remind Anakin who he is. He's "that little boy on Tatooine." In the end, it is Padmé and her loyal maiden Sabé who save Darth Vader, and save the galaxy.