For sure Naruto is the main focus as he is the one being trained. Among the RWBY characters, Ruby is likely to be a main character as she has the most open - minded and inclusive nature which would make her eager to train Naruto. Weiss, with her precision and strict training methods, would play a significant role. Blake's stealth and Yang's brute force would also make them important main characters in the fanfiction as they interact with Naruto during his training.
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.
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.
Well, Naruto for sure. His immortality gives him a unique place in the story. From RWBY, Yang Xiao Long could be a main character. Her brash and confident fighting style would create an interesting dynamic with Naruto. Blake Belladonna, with her mysterious past and cat - like abilities, might also be a central figure. Her more reserved nature compared to Naruto's open - heartedness could lead to some great character development moments. And of course, Ruby and Weiss as mentioned before, would also be important in shaping the story around an immortal Naruto in the RWBY world.
Obviously, Naruto and Tenzo would be the main characters. Naruto, as the one being trained, is the protagonist of the Naruto series. And Tenzo, with his unique skills, is the trainer in this fanfic.
Obviously, Naruto and Deadpool would be the main characters. Naruto is the one being trained and evolving into a 'godlike' state. Deadpool is the trainer who brings his own set of skills and personality to the story.
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.
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.
Obviously, Harry and Merlin are the main characters. Harry is the one being trained, and Merlin is the trainer.
Obviously Naruto would be one of the main characters as the title implies he is the one being trained. King Kai would also be a major character as he is the trainer. There might also be some cameos or interactions with Dragon Ball Z characters like Goku or Vegeta, since the fanfiction combines the two universes.
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.