A young artist from a neighboring kingdom could be introduced. He hears about the Beast's castle and is intrigued by the rumors of its beauty and mystery. When he arrives, he could befriend Belle and see the relationship between her and the Beast. His unique perspective as an artist could add a different dimension to the story, like he could paint pictures that somehow affect the curse.
A character who is a master of shadow puppetry, but not in the normal sense. Instead of just creating simple shapes, they can create entire landscapes and armies of shadow creatures. This character could have a mysterious backstory and their own motives, which could either make them an ally or an enemy in the fanfiction.
A psychic human. This character could sense the demons' movements and intentions before they attack. They could use their powers to help the Doom Slayer or other marines, for example, by warning them of an ambush or guiding them through a maze - like area filled with demons.
A character from a different dimension who is a master of technology could be added. This character could use their technological knowledge to analyze the magic of the rings in ways that the people of Middle - earth can't. For instance, they might be able to detect hidden spells on the rings using some kind of advanced scanner.
How about a magical mermaid who lives in a hidden lake in the world of Sonic and the Black Knight? She could have the power to heal Sonic when he's injured and give him clues about the secrets of the Black Knight's sword, but she also has her own motives and secrets that Sonic has to figure out.
A character like a water spirit that has the power to change the tides. This spirit could be both a friend and a mentor to Ariel. It could teach her about the deeper secrets of the ocean and how to use the power of the water to her advantage. Also, a young mermaid princess from a neighboring kingdom who is very competitive with Ariel. They could start off as rivals but then become friends through various adventures. This would add a new dynamic to the story.
An ancient demigod who was frozen in time and now awakens in the modern Percy Jackson world. This character has archaic ways of thinking and fighting but also has knowledge of long - forgotten prophecies and secrets that could either help or hinder Percy. They might have a different view on the gods and their roles compared to the modern demigods. For instance, they could believe in more direct worship and obedience, which would clash with Percy's more laid - back attitude towards the gods.
A half - vampire half - werewolf character could be added. This character would be constantly at war with themselves due to their dual nature and could add a whole new layer of drama. They might befriend the vampire's assistant and introduce them to a world that is a blend of both vampire and werewolf cultures.
In a crossover with the Mortal Kombat universe, characters like Scorpion or Sub - Zero could be added. Their unique fighting styles and powers would add a new dimension to the Avengers' battles. Another character could be Goku from Dragon Ball Z. His super - strength and ability to fly and use energy blasts would make for some exciting interactions with the Avengers.
A character who is a descendant of an ancient clan that once had a connection to the Nine - Tails could be added. This character could have some knowledge about the Nine - Tails that was lost over time and could help Naruto better understand his power.
A character like a time - traveling demigod from the future could be really interesting. This character could have knowledge of events that are yet to happen in Percy's world and could either help or hinder him depending on their motives.