He might be interrogated by the captors. They could try to extract information about the Sith, the Empire's secrets, or his own powers. Maybe they would attempt to turn him against the Emperor, using various means like appealing to his remaining humanity or threatening him with things he values.
In fanfiction where Darth Vader gets captured, one possibility is that he's captured by a new, unknown force. This could be a group from a far - off planet or an ancient order. They might not fully understand who he is and the danger he poses. As a result, Vader could use this to his advantage, playing on their ignorance. He might also face internal struggles during his captivity. Despite being a Sith, there could be a part of him that questions his loyalty to the Emperor, especially if his captors present him with alternative views of the galaxy and the Force.
Well, if Darth Vader gets captured in fanfiction, it could lead to some really interesting scenarios. His captors might be a group of rebels who see this as a huge opportunity. They could try to remove his suit to weaken him or study his cybernetic enhancements. However, Vader is extremely powerful, so even captured, he would likely be a formidable force. He might use the Force to try and escape, or perhaps manipulate his captors into believing he's on their side while secretly planning his revenge.
He might try to change his own fate. For example, he could prevent himself from turning to the dark side in the first place. Maybe he would warn his younger self about Palpatine's true intentions.
In a 'Ahsoka meets Darth Vader' fanfiction, there could be an intense battle. Ahsoka, with her Jedi skills, would be a formidable opponent to Vader. Maybe she tries to redeem him, recalling the Anakin she once knew. Or perhaps Vader sees her as a threat to the Empire and attempts to eliminate her quickly.
Well, one possibility is that Ahsoka tries to redeem Vader. She might see a glimmer of Anakin still in him and strive to bring him back to the light side. It would be a very emotional encounter, full of memories of their past as master and apprentice.
Well, in fanfiction, when Darth Vader meets Yoda, it could lead to a battle of ideologies. Vader, having turned to the dark side, represents power and control through the Sith ways. Yoda stands for the Jedi's connection with the Force in a more harmonious and selfless way. They could engage in a Force - powered duel where Vader tries to overpower Yoda with his dark side strength, but Yoda uses his wisdom and experience to counter.
Well, it could be a really wild story. Harry's magic might interact in strange ways with Darth Vader's Force powers. Maybe Harry would try to use his spells to resist Vader's dark side influence.
In a 'naruto gets captured' fanfiction, he might be tortured for information. His captors could be after the secrets of his Nine - Tails chakra. They may try to use him as a bargaining chip against Konoha.
Well, in this fanfiction, perhaps Steven could be held captive by an old enemy. Maybe he'll have to use his wits to escape, like finding a weakness in the prison's security system.
Well, perhaps Gengar is captured by a powerful trainer. The trainer might use a special Poké Ball to catch it. Then, Gengar could try to escape from the ball by using its ghostly powers.
In this fanfiction, Luffy might be used as a bargaining chip by his captors. Maybe they'll try to exchange him for something valuable, like a powerful Devil Fruit or a large amount of treasure. His crew would then surely launch a rescue mission, facing many challenges along the way.
In this fanfiction, perhaps Serena is captured by an evil organization. They might be after her special powers or knowledge. Then, her friends would start a rescue mission.