It really depends on how you write it. If it's Anakin at his peak before turning to the dark side, he has a lot of raw power and potential. But Vader has years of experience as a Sith Lord. So, it could go either way.
Luke Skywalker could be another key character. Since he is Vader's son, his presence could add an interesting dynamic. He might be the one who somehow triggers the battle between Anakin and Vader, or he could be in a position to influence the outcome of their fight, perhaps by appealing to the remaining good in Anakin or by facing off against Vader himself in a three - way struggle.
One idea could be a what - if scenario where Anakin in his pre - Vader state somehow gets a glimpse of his future as Vader. He could then fight against the dark side within himself that would turn him into Vader. Another could be a time - travel plot where Vader is sent back to face Anakin, and Anakin has to decide whether to accept his possible future or fight against it.
A fan fiction could also explore a parallel universe where Anakin and Darth Vader are two separate entities that co - exist. They are forced to fight not because of Anakin's fall, but due to some external force that wants to see the two most powerful Sith - like beings battle it out. This could lead to an exploration of their different fighting styles and the power dynamics between them.
No, it's not a very popular genre in the general sense. Hitler is a highly controversial and abhorrent figure in history, and many people may be uncomfortable with fictionalizing his story. However, there are some niche audiences, particularly those interested in alternate history or in exploring the depths of historical evil through fictional means, who might be interested in such works.
Adolf Hitler was born in Austria in 1889. He had a rather difficult childhood. He then moved to Germany and got involved in politics. Hitler rose to power in the 1930s. He was the leader of the Nazi Party. His extreme racist and anti - Semitic beliefs led to World War II and the Holocaust, which was the mass murder of six million Jews. His actions brought great destruction to the world.
Hitler started as a failed artist. He then turned to politics. He blamed the Jews for Germany's problems after World War I. He formed the Nazi Party and gradually took over the German government. He built up a powerful military and invaded many countries, believing in the superiority of the Aryan race and trying to create a so - called 'Greater Germany' which would dominate Europe.