A new Akatsuki member, a young and powerful ninja who has a personal vendetta against Naruto. Their clashes could add a lot of drama and action to the fanfic.
There could be a group of orphans who have banded together and developed their own unique style of ninjutsu out of necessity. These orphans could add a new dimension to the story as they struggle to survive in a world full of powerful ninjas while also trying to find their place in it.
In a 'henceforward rwby fanfic', a new character could be a young boy from a nomadic tribe in Remnant. His semblance is the ability to sense danger from miles away, which has kept his tribe safe for generations. He could join the RWBY gang on their adventures, bringing with him a different perspective on the world. Another potential character is a female knight from an ancient order in Atlas. She has a very strict code of honor and her semblance is the ability to make her armor impenetrable for a short period. Also, a character from a hidden underground city in Remnant could be introduced. This character has a semblance that allows them to phase through solid objects and could provide some interesting plot twists in the fanfic.
A character could be a mysterious guide who knows all about this 'another world'. He or she could be an old hermit who has lived in this world for a long time and has unique powers related to the world's natural elements.
A skilled samurai girl from the Iron Country. She could be a master of a unique sword - fighting style. Maybe she initially distrusts Naruto because of the differences between ninja and samurai, but later becomes his ally and friend.
A powerful elder who has been in hiding since the fall of the Land of Whirlpool. He could have a vast knowledge of the land's ancient techniques.
A species - specific character like a Chiss bounty hunter. The Chiss are known for their intelligence and strategic thinking. This bounty hunter could be on a mission to capture a high - profile target in the Star Wars Visions universe. They would use their unique Chiss abilities, such as their natural aptitude for tactics, to outwit their opponents.
A potential new character could be a mysterious sage who has a deep understanding of both Oriko Jutsu and the Kyuubi. This character could be a mentor figure to the protagonist, guiding them in their journey to master the jutsu and deal with the Kyuubi's power.
A new character could be a rogue ninja from a clan that was wiped out during the Warring States Era. He could be on a revenge mission against the clans that destroyed his own. This character would bring a sense of mystery and danger.
A new demigod from a previously unheard - of god or goddess. Maybe a child of a minor deity who has some unique powers that could either help or hinder Percy in the situation of the collapse. For example, a child of Hypnos who can manipulate sleep and dreams, and their powers could be used to either give Percy visions of how to fix things or put him in a dangerous trance.
A potential new character could be a magical art teacher who has the ability to bring out the best in Evillustrator's powers. Another could be a street artist who becomes friends with Evillustrator and gets caught up in the superhero - villain drama. Maybe a young aspiring artist who looks up to Evillustrator and tries to help him turn good.