The main characters would surely be Anakin Skywalker and Count Dooku. Anakin is the protagonist in a sense as we would see his development through Dooku's training. Dooku, on the other hand, is the one who imparts his knowledge and skills, and his character would also be explored in terms of his motives for training Anakin.
Well, the most prominent characters are bound to be Anakin and Dooku. However, there could also be other characters who play important roles. For example, Obi - Wan Kenobi might sense something strange about Anakin's behavior during his training with Dooku and start to investigate. Or Palpatine could also be involved, as he has his own interests in Anakin. But at the core, it's Anakin's journey under Dooku's tutelage that would be the focus, so they are the main characters.
Obviously, Anakin Skywalker and Revan. Anakin is the one being trained, so he will be a central figure. His growth and development under Revan's tutelage will be a major focus.
In this fanfiction, the plot could center around Anakin's struggle with the two different ideologies of the Jedi and Dooku. Dooku, as his trainer, might expose Anakin to the Sith ways. This could lead to Anakin having internal conflicts, as he has to decide whether to stay loyal to the Jedi or follow Dooku's path. His training could involve learning more aggressive and unorthodox Force abilities that are frowned upon by the Jedi, and his interactions with Dooku could gradually change his view of the galaxy and his place in it.
Anakin's mother, Shmi, would likely be a very important character. Since Anakin is not being trained as a Jedi, he would be more focused on his family. Shmi's influence on Anakin would be even greater, and she could play a role in guiding his actions and decisions, especially in relation to the local community on Tatooine.
The main characters would be Naruto and Hiruzen. However, we might also see characters like Kakashi make an appearance. Kakashi could be a bit jealous at first that Hiruzen is taking Naruto under his wing, but then he might see the benefits and offer his own advice to Naruto on the side.
Obviously Naruto would be one of the main characters as the title implies he is being trained. And then, the RWBY characters like Ruby, Weiss, Blake and Yang would also be main characters since they are the ones doing the training.
Obviously, Harry and Merlin are the main characters. Harry is the one being trained, and Merlin is the trainer.
The main characters would be Anakin Skywalker and Darth Plagueis. Anakin, a powerful Force - sensitive, is the focus of the training. Darth Plagueis, a Sith Lord, brings his knowledge of the dark side of the Force to the table. There may also be other supporting characters like the Jedi who might notice Anakin's change in behavior or Padmé, Anakin's love interest, who could be affected by his new training and the path he is on.
In addition to Naruto and Anakin, the fanfiction might introduce some Naruto - universe characters into the Star Wars setting. For example, Sasuke could show up. His rivalry with Naruto could translate into some sort of conflict or cooperation in the new universe. And of course, the Sith Lords would be there as the antagonists. They would be interested in Anakin's potential, and Naruto would have to protect his son from their influence.
Obviously, Harry Potter and Flitwick are the main ones. Harry as the student being trained and Flitwick as the trainer.
Obviously, Harry Potter would be one of the main characters. And then, there would probably be some members of the SAS. They could be tough, experienced soldiers who take on the task of training Harry.