A cool concept for a Shadowhunters fanfic could be a crossover with another fantasy series. Imagine if the Shadowhunters had to team up with characters from, say, The Mortal Instruments. Or you could focus on the relationships between characters in a new way. Maybe write a fanfic about Alec and Magnus during their first year of marriage, dealing with all the new challenges that come with it.
One idea could be exploring a different origin story for a main character. For example, what if Jace had a different family background that changed his path in the Shadowhunter world. Another idea is a time - travel fanfic, where a character goes back in time and has to deal with the consequences of changing past events. It could also be interesting to write a fanfic about a character who has lost their powers and how they cope and try to regain them.
You could write a fanfic centered around a new threat to the Shadowhunter world. A powerful demon that has a unique ability that the Shadowhunters have never faced before. This would force them to come up with new strategies and alliances. Also, a fanfic about the training of the younger Shadowhunters, showing their growth and development, could be really engaging.
Another option is a crossover with the Harry Potter universe. The Shadowhunters could end up at Hogwarts, perhaps because there is some sort of dark magic that is spilling over into the mundane world that they need to stop. They would be amazed by the magic in the wizarding world, and there could be some funny moments as they try to understand how things work there, while also trying to keep their own identities and purposes a secret from the wizards.
A fanfiction could explore the idea of a character from Twilight becoming a Shadowhunter. For example, Bella could discover she has Shadowhunter blood and has to leave the vampire - werewolf drama behind to learn a whole new set of skills and rules in the Shadowhunter world. It would be interesting to see how she adapts and how her relationships with Edward and Jacob change as a result.
Another plot could involve an OC who comes from a long - lost line of Shadowhunters. They bring back an ancient fighting style or a forgotten weapon. This OC could be on a quest to rediscover their family's past and in the process, they end up uncovering secrets about the Shadowhunter world that could change everything. Maybe they find a hidden lair with powerful artifacts that were thought to be lost forever.
A plot could involve a Twilight vampire falling in love with a shadowhunter. The vampire has to deal with the shadowhunter world's rules about the supernatural, and the shadowhunter has to come to terms with loving a vampire, which goes against their training. This could lead to a lot of internal and external conflicts as they try to be together.
One idea could be a crossover where the characters from both universes team up to fight a common supernatural threat that is a combination of demons from Supernatural and Downworlders from Shadowhunters. For example, a powerful demon has made a pact with a group of rogue vampires to take over both the human world and the Shadow World.
One plot idea could be that the Shadowhunters need to find a way to defeat a powerful demon that can only be weakened by a special type of music. So they seek out the Glee club. The Glee club members are hesitant at first but then realize the importance of their role. Another idea is that a spell gone wrong in the Shadowhunters' world sends some of their key characters to the Glee club's world. There, they have to adapt to high school life while also trying to find a way back. And the Glee club helps them blend in and in return, they learn about the Shadow World.
One idea could be that Magnus kidnaps a Shadowhunter to force them to reveal a secret that could save the Downworld. He might believe this Shadowhunter has crucial information that the Nephilim are hiding. Another could be that Magnus is being controlled by a dark force and kidnaps someone as part of its evil plan. Then, the kidnapped person's friends have to find a way to break the control on Magnus and save their friend.
One interesting plot twist could be when a beloved Harry Potter character is revealed to have a hidden Shadowhunter heritage. This completely changes their identity and the way they interact with both worlds.
Another scenario could be that Clary has to choose between her duties as a Shadowhunter and her love for Simon. She loves the Shadowhunter world and wants to protect it, but she also loves Simon deeply. In the fanfic, she might find a way to balance both, which is a great exploration of their love.
No. 'Shadowhunters' is a popular series, and fanfic often involves unregulated and potentially inappropriate content like sexual themes which go against the original intended audience and values of the source material.