It's hard to say it's a widely 'popular' genre. While there are some fans who might be interested in exploring darker themes with Darth Vader in fanfiction, the idea of torture is a rather extreme and niche aspect. Many in the Star Wars fan community are more drawn to stories about heroism, adventure, and the battle between the light and dark side in a more general sense.
In the Star Wars fanfiction community, 'darth vader x oc torture fanfiction' is not a common or popular genre. The Star Wars franchise is mainly known for its epic space battles, the struggle between the Force - light and dark, and the complex characters. Torture is a very specific and often uncomfortable theme. Only a small number of fans who are interested in exploring the darker and more extreme aspects of Darth Vader's character might be into this type of fanfiction. Most fans focus on other aspects that are more in line with the overall spirit of Star Wars.
I don't think it's a very popular genre. The Star Wars franchise is mainly known for its epic battles, cool characters, and the struggle between good and evil. Fanfiction usually focuses on expanding on these elements rather than on torture. However, there might be a small group of fans who are interested in exploring the psychological and darker aspects of the Star Wars world through such fanfiction, but it's not widespread.
One ethical concern is the glorification of violence and torture. It can be disturbing to readers who don't expect such extreme and dark content in the context of Star Wars. Also, it might cross the line into creating a very negative and unethical portrayal of a character, even one as dark as Darth Vader.
There's a fanfic titled 'Vader's Redemption'. In this story, Vader starts to question his loyalty to the Emperor much sooner, especially after some profound encounters with Luke. It's a great read as it shows the internal struggle of Vader while also exploring the bond between father and son in a new light. It's full of action-packed scenes and deep emotional moments.
One popular theme is Vader's struggle with his identity. During the Clone Wars, he was still Anakin Skywalker in many ways, so fanfictions often explore his internal conflict. Another theme is his relationship with the Jedi. Since he was on the verge of becoming a Sith, how he interacted with the Jedi during the Clone Wars is an interesting area. And power - his thirst for power and how it grew during the Clone Wars is also a common theme.
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.
Well, a really good fanfiction is 'Darth Vader: Clone Wars Origins'. It gives a unique perspective on how Vader's character might have developed during the Clone Wars. It has some great action scenes and explores his relationship with other key characters like Palpatine. Another one to check out is 'Vader in the Clone Wars: The Untold Story'. This fanfic fills in some gaps in the official story and shows Vader's influence on the events of the Clone Wars in a different light. And then there's 'Clone Wars: Vader's Redemption', which takes a more speculative approach to Vader's character and his potential for change during the Clone Wars.
There could be fanfictions that focus on Darth Vader's secret missions during the Clone Wars. Missions that the Jedi didn't know about.
One interesting female Darth Vader fanfiction is 'The Empress of the Sith'. It reimagines Vader as a female character and delves into her rise within the Sith order. The story has great character development and some intense lightsaber battles.
Darth Vader was once Anakin Skywalker, a Jedi with great potential. But he was lured to the dark side by Palpatine. He became a Sith Lord. Vader was a fearsome figure in a black suit with a red lightsaber. He carried out the Emperor's evil commands, like hunting down Jedi. However, in the end, he redeemed himself by saving his son, Luke Skywalker, from the Emperor's wrath at the cost of his own life.
Darth Vader was once Anakin Skywalker, a Jedi with great potential. He was lured to the dark side by Palpatine. His fall was tragic. He became a Sith Lord, a powerful enforcer for the Empire. He wore the iconic black suit and had a menacing presence. He was involved in many battles, like the destruction of Alderaan. In the end, he redeemed himself by saving his son, Luke Skywalker.