There could be a leader of the horde. This character might be initially skeptical of Naruto but later comes to respect him. Another character could be a young member of the horde who looks up to Naruto as a role model and wants to learn from him.
Maybe there is a rival within the horde who doesn't like Naruto joining at first. This rival could be jealous of the attention Naruto gets. There might also be an elder in the horde who has a lot of wisdom and acts as a guide to Naruto in understanding the horde's culture.
It's possible that there is a female character in the horde who is intrigued by Naruto. She could be the one who helps Naruto adapt to the horde's lifestyle at the beginning. And there could be a strong warrior in the horde who challenges Naruto to prove his worth in joining them.
Well, it could be about Naruto finding a new group to belong to. Maybe he's lost in a strange world and the horde takes him in. He might bring his ninja skills and unique values to the horde, causing all kinds of changes in their way of life.
Besides Naruto, Yugito Nii could be a main character. She is a jinchuriki in Kumo, just like Naruto is in Konoha. They could bond over their shared experiences of being hosts. And there could be some of the Kumo elders who play important roles. They might be the ones who oppose Naruto's entry at first, fearing he could bring trouble, but then as they see how he can contribute to the village, their opinions change.
Another possible main character could be Shino Aburame. He is Naruto's friend and has his own unique abilities. In the context of Naruto joining the Inuzuka clan, Shino could offer a different perspective. He might not be from the Inuzuka clan but could provide advice to Naruto on how to adapt to a new clan environment. Also, his interactions with the Inuzuka clan members could add more depth to the story, for example, his bugs interacting with the Inuzuka dogs in some unexpected ways.
Bulbasaur - girl might be a great choice too. Her connection with nature and plant - based attacks could add an interesting dynamic. She could help Naruto understand the Pokemon world better, especially when it comes to things like finding herbs or dealing with forest - related challenges. There could also be a fiery - tempered Charmander - girl who provides a contrast to Naruto's more easy - going nature and has her own set of powerful fire - type attacks.
It could be a mysterious figure who uses the locust horde as a weapon to take over the ninja world. This person might have some grudge against the existing ninja villages and sees the locusts as a way to disrupt their peace.
Obviously, the Jedi who adopt Naruto would be main characters. For example, a Jedi Master like Obi - Wan Kenobi could be the one to discover Naruto and take him under his wing. Another could be Yoda, who would be very interested in Naruto's unique abilities and would play a role in his training. There could also be other young Jedi trainees who become Naruto's friends or rivals during his time at the Jedi temple.
Sasuke could be one of the main characters. He might initially be skeptical about Naruto's new identity but then come to accept it and fight alongside him. Sakura could also be there, perhaps using her medical skills to help Naruto when he gets injured during his adventures related to his Pegasus heritage.
One of the main characters could be Fleur Delacour. Since she's from Beauxbatons, she might be the one to first interact with Naruto. She could be curious about his strange abilities and help him adjust to the school. Another could be a male student at Beauxbatons who is initially jealous of Naruto getting all the attention but later becomes his friend after seeing his true character.
Maybe there are new characters created specifically for this fanfiction. They could be local inhabitants of the wet area, such as a water nymph - like character who has knowledge about the secrets of the place and either helps or hinders Naruto's journey.
Lelouch could be a main character. Since he is a key figure in the Code Geass world which has Britannia. He and Naruto might start as rivals due to their different approaches to justice but later become allies. Suzaku could also be involved. He might be initially suspicious of Naruto but come to respect him as Naruto shows his good intentions in the Britannian world.