Sakura would be a likely main character. She is a skilled medical ninja, so she could play a crucial role in ensuring the health of those involved in the repopulation efforts. For example, she could develop new medical procedures to help with childbirth or deal with any potential health issues that might arise during pregnancy.
Hinata would be another important character. Given her love for Naruto, she would be very involved in the repopulation efforts. She could be in charge of teaching the younger generation about family values and how to raise children in a post - war world. Her gentle nature would be an asset in creating a nurturing environment for the new population.
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.
There could be a kunoichi who is a master of stealth and espionage. She might be the first to discover Naruto's arrival in the kunoichi world. Another main character could be a kunoichi with a strong sense of justice, similar to Naruto. She would be the one to advocate for Naruto when others are against him. And perhaps there's a kunoichi who has a special connection to an ancient power in this world, and she and Naruto's Juubi power somehow interact in an unexpected way throughout the story.
Maybe in the fanfiction, a strange disease has made it difficult for people to have children. Naruto discovers a new form of chakra - based medicine that can reverse this. He then travels around the world, teaching others how to use this medicine and also promoting the idea of having more children. This could lead to different adventures as he faces opposition from some who don't believe in his methods.
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.
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 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.
Hinata could be one of the main characters. She might support Naruto in his efforts to rebuild the Whirlpool Village, both morally and with her Byakugan skills which could be useful for scouting and security.