Darth Vader could encounter advanced droids that have developed personalities and even some form of Force - like abilities in this future. These droids might be a new challenge for him as they are not like the droids he is used to dealing with in his own time. He may also meet future versions of his former allies or enemies, who have been reincarnated or cloned in some strange new way, with different personalities but still with a connection to their past selves.
In such a fanfiction, Darth Vader might try to prevent his fall to the dark side. He could use his knowledge of the future to avoid the events that led him to become a Sith. For example, he might prevent the death of his mother or his duel with Obi - Wan on Mustafar.
In such a fanfiction, Darth Vader could change the course of history. He might prevent the rise of the Empire or alter his own fall to the dark side. For example, he could warn Anakin Skywalker about Palpatine's true intentions, thus changing the entire Star Wars timeline.
In the 'Darth Vader travels to the future fanfiction', it could be that he ends up in a future where the galaxy is at peace. There are no wars, and the Jedi have evolved into something different. Vader, being from a time of conflict, struggles to adapt. He may be seen as a relic of a more violent era. However, he also holds knowledge that could be valuable. Maybe he teams up with some future characters to prevent a new threat that is emerging, using his unique skills and the power of the dark side, while also being tempted to turn away from his dark past.
In the fanfiction where Darth Vader travels back in time, his bond with Obi - Wan Kenobi would be full of possibilities. Imagine Vader going back to a time when he was still Anakin. He might have a newfound respect for Obi - Wan, knowing all that Obi - Wan tried to do for him in the future. Obi - Wan, for his part, could be shocked to see this changed Anakin. They could form an alliance against the emerging threat of the Sith, or Vader could try to get Obi - Wan to understand his view of the Force. Their relationship would no longer be simply that of a Jedi and his fallen apprentice, but something far more nuanced and unpredictable.
Darth Vader could meet advanced droids that have personalities and abilities far beyond what he's used to. These droids might see him as a relic from a bygone era. He could also meet future scientists who are intrigued by his cybernetic enhancements and try to study him. Additionally, there's a chance he meets descendants of his former allies or enemies, which would create a complex web of relationships and interactions.
He could meet his younger self, Anakin Skywalker. That would be a really interesting encounter. He might also meet Qui - Gon Jinn, who could sense the conflict within him. And there's a chance he'd cross paths with Yoda in his prime, which would lead to some intense confrontations or perhaps even unexpected alliances.
His presence could change the power balance. If he sides with the Jedi, the Sith would be at a disadvantage. The Sith rely on secrecy and manipulation, but with Darth Vader knowing their plans, they would be exposed more easily.
He might be shocked by the advanced technology. The Empire's weaponry would seem primitive compared to future tech. He could also be intrigued by the new forms of the Force if they had evolved.
Darth Vader was originally Anakin Skywalker. He was a slave on Tatooine. Qui - Gon Jinn discovered his strong connection to the Force and took him for Jedi training. Anakin had great potential but was haunted by fear, especially of losing his loved ones. His relationship with Padmé Amidala led to his downfall. He turned to the dark side under the influence of Palpatine, who promised him the power to save Padmé. After a fierce battle with Obi - Wan Kenobi, he was severely injured and transformed into Darth Vader, becoming a powerful enforcer for the Galactic Empire.