One interesting character could be the White Rabbit. In the fanfic, he could be a messenger who mistakes Naruto for someone else. Naruto would have to chase him to clear up the misunderstanding. Another would be the Queen of Hearts. She could be a powerful antagonist, trying to execute Naruto for not following her strange rules. And of course, Naruto's friends from his own world could also make cameo appearances in Wonderland in some magical way.
He could meet the Mad Hatter. The Mad Hatter would be an interesting character for Naruto to interact with as he's so unpredictable and has his own strange way of seeing the world.
The main characters would be Naruto and his friends from the Leaf Village. But in Halloween Town, we could see some characters inspired by classic Halloween figures. There could be a Jack - o' - lantern - headed merchant who sells strange items. A mummy - like ninja who is very slow but has incredible strength. And a ghostly figure who was once a great ninja but got trapped in Halloween Town and now gives Naruto advice on how to defeat the forces that lurk in the shadows of the town.
In this fanfiction, characters like Hagrid could also be involved. He could befriend Naruto and introduce him to the more positive aspects of the wizarding world. And of course, there could be other Death Eaters who might either try to use Naruto or see him as a threat due to his relation to Bellatrix.
Obviously Naruto would be the main character. There could also be the forest spirits which could be original characters created for this fanfiction. Maybe some of Naruto's friends like Sasuke or Sakura might make an appearance, either to help Naruto in his forest - related challenges or to try and bring him back to the village if they think he's spending too much time in the forest.
Well, Naruto is the key character here. Then we could have other Naruto characters like Jiraiya. In the Olympian part, Hermes could be a character as he could be the one to guide Naruto in the Olympian world. Also, Aphrodite might be there, perhaps using her charm powers to either help or hinder Naruto. And in the Naruto world, we can't forget characters like Gaara who might react in different ways to Naruto's newfound Olympian identity.
One potential character could be Kakashi. He would probably be very confused and concerned about Naruto's situation. He might try to train Naruto to control his powers in a way that doesn't harm himself or others. Another character could be Tsunade. As the Hokage, she would have to decide how to deal with Naruto. She could either support him or try to keep him in check. And of course, there could be some villains from the Deathwing side who come to either recruit or destroy Naruto.
Obviously Naruto would be the main character. Shukaku itself or a representation of Shukaku's spirit could be there. Also, characters like Iruka sensei would still be around. His friends like Sasuke and Sakura would play important roles as they react to Naruto's new situation.
Obviously Naruto himself. Then there could be other Naruto characters like Sasuke and Sakura who would react to Naruto's new heritage. Also, characters related to Mileena might be introduced, perhaps some of her allies or enemies from her own story.
Tenten could potentially be in the harem. She is a strong - willed and capable kunoichi. Her presence in the harem could add an element of action and adventure. Maybe she initially tries to fight against the evil Naruto but then gets drawn into his world and eventually becomes part of his harem.
A new, original character could be the main character in a Naruto chains fanfiction. This character could be from a small, unknown ninja village and possess a unique ability to control chains made of some special material. They could come to the Hidden Leaf Village and get involved in the events there, interacting with the well - known Naruto characters.