What are some interesting ideas for a Star Wars Darth Vader crossover fanfiction?

One idea could be a crossover with Star Trek. Darth Vader could find himself on the Enterprise and have to deal with the Federation's values, which are very different from the Sith's. Maybe he'd be forced to team up with Kirk and Spock to fight a common enemy.

A plot could involve Darth Vader having visions of a different future where he and Princess Leia are on the same side. These visions start to haunt him, and he begins to subtly protect her from the Emperor's wrath. In the meantime, Leia senses a change in Vader's behavior and tries to figure out if she can use this to the advantage of the Rebel Alliance. For example, she might try to convince him to turn against the Empire completely.

One idea could be that you insert yourself as a new apprentice to Darth Vader. You start with basic training, learning the ways of the dark side from him. Maybe you discover a hidden power within the Force that Vader is also intrigued by, and together you explore its potential.

In some fanfictions, Darth Vader's redemption is linked to his relationship with his daughter, Leia. Maybe he discovers her identity before the events in 'Return of the Jedi' and starts to change his ways in order to protect her and make amends for his past actions. He could start to undermine the Empire from within to ensure her safety.

One interesting story could be about Darth Vader secretly having a change of heart during the events of Star Wars Rebels. Maybe he has a brief encounter with a Rebel that makes him question his loyalty to the Empire.

In some fanfiction, there could be a scenario where Leia discovers her connection to Darth Vader much earlier. Maybe she has a vision or some sort of Force - related encounter that reveals the truth. This would lead to a very different dynamic in the story as she grapples with this knowledge and how it affects her fight against the Empire. For example, she might try to reach out to the good in him, creating an internal struggle for Vader between his loyalty to the Emperor and his newfound connection to his daughter.

One interesting fanfiction could be about Darth Vader secretly having a moment of hesitation when facing a Rebel who reminds him of his past self. Maybe he lets the Rebel escape without the Emperor knowing. It adds a new layer of complexity to his character.

One plot idea could be that R2D2 is captured by Darth Vader. But instead of destroying the little droid, Vader becomes curious about the information it might hold. He tries to hack into R2D2's memory, leading to a series of tense moments as R2D2 tries to protect the secrets within. Maybe R2D2 has some long - lost Jedi knowledge that Vader thinks could help him overthrow the Emperor.

One scenario could be that Darth Vader discovers Ahsoka is still alive and is conflicted between his Sith loyalty and his past connection with her. He might secretly try to protect her from other threats in the Empire without revealing his identity.

Well, a cool plot might be that Ahsoka gets trapped in a Sith - created illusion world by Vader. In this world, she has to face her past traumas and fears related to Anakin's fall. Meanwhile, Vader is conflicted as he watches her struggle, memories of his past with Ahsoka resurfacing. Or there could be a story where they both are on a mission to retrieve a powerful Jedi/Sith artifact, and their paths cross in a race against time.