There could be a fan fiction where Charlie and Bill are part of a mystery-solving duo. They use their unique skills, Charlie's knowledge of certain creatures perhaps and Bill's experience from his travels, to solve a mystery in their town.
To write a good Charlie and Bill fan fiction, you need to know the characters well. Consider their personalities. Charlie is often seen as more reserved while Bill is more adventurous. Use these traits to create interesting dialogues and situations for them.
They could be like brothers. Harry has a strong connection with the Weasley family already, and with Bill and Charlie, it could be a natural extension of that. They might look out for each other and support one another in any difficult situation.
Charlie Charlie is purely fictional. It emerged as a form of online folklore or myth that lacks any credibility or factual foundation. People often enjoy the thrill of it without taking it seriously as real.
They could help Harry by teaching him new spells. Bill might teach him some advanced defensive spells he learned as a curse - breaker. Charlie could show Harry some unique ways to use magic around magical creatures. Hermione would of course be there to ensure Harry studies hard and understands the theory behind the spells.
In a fanfiction scenario, perhaps Hermione has a research project and enlists the help of Bill, Charlie, and Harry. Bill could offer insights from his travels, Charlie might contribute with his expertise on dragons as it relates to the research, and Harry would be there for moral support and to offer his unique perspective as the Boy Who Lived. It could be a story of friendship and cooperation in the magical community.
The Bill Cipher triangle can also be a way to connect different plotlines in fanfic. For example, one group of characters might be researching its history while another is trying to stop it from being activated. This creates a complex web of storylines that all revolve around this one mysterious triangle.
One great Hermione, Bill, Charlie, Fred, and George fanfiction could be a story where they all team up for a dangerous magical quest. Maybe they have to find a lost artifact that is crucial for the wizarding world. Hermione's intelligence would lead the way in researching about the artifact, while the Weasley brothers - Bill with his worldly experience, Charlie with his dragon knowledge, and Fred and George with their creativity and mischievousness - would contribute in different ways like handling the physical challenges along the way.
There's a fanfiction where Bill, Charlie and Percy are on a quest related to spiders. It shows how their different skills come into play. Bill's worldly knowledge, Charlie's connection with magical creatures, and Percy's strategic thinking all combine to make for an exciting adventure. They face all sorts of spider - related challenges that keep you on the edge of your seat.