One idea could be creating an OC who is a long - lost relative of a main character. For example, an OC could be Natsu's sister who was separated from him at a young age. This OC could have unique fire - based magic that is different from Natsu's. Another idea is an OC from a different dimension that gets trapped in the Fairytail world. They could bring new types of magic and technology from their own world, causing chaos and new adventures.
An interesting Fairytail OC fanfiction idea is an OC that is a half - human, half - spirit. They have the ability to communicate with spirits easily and use their powers to help the Fairytail guild. Maybe they can even call upon powerful spirit allies during battles. Or, you could have an OC who is a reformed dark mage. They used to be on the wrong side but now want to prove themselves to the Fairytail guild and has to overcome the prejudice of the members.
You could create an OC that is a traveling merchant with a special ability to sense magic items. This OC could stumble upon the Fairytail guild while on a business trip and end up getting involved in their adventures. Their knowledge of rare magic items could be very useful to the guild. Also, an OC who is a mermaid - like creature that can transform into a human on land and has a connection to the underwater magic in the Fairytail world would be a cool concept for a fanfiction.
Another idea is that the OC is a mage who can transform into a cat - like Pantherlily. But they are not fully in control of this power. Pantherlily takes it upon himself to train the OC to master this ability. Along the way, they get involved in a guild - wide competition where the OC has to prove their worth not just as a cat - like mage but also as a true Fairy Tail member.
You could have an OC who is a gamer in the real world but gets transported into the Fairytail universe. At first, they struggle to adapt but then realize that their knowledge of games can help them understand the magic system better. For instance, they might compare the different types of magic to character classes in RPGs and use this knowledge to develop their own unique magic skills.
One idea could be a crossover where Naruto characters gain the magic abilities of Fairytail wizards. For example, Naruto could learn fire magic like Natsu. Another idea is a story where the guilds in Fairytail and the villages in Naruto have to team up to fight a common enemy, like an ancient evil that threatens both worlds. A third idea might be a fanfiction where a Fairytail wizard ends up in the Naruto universe and has to adapt to their way of life, while also sharing their magical knowledge with the ninja.
One interesting plot idea could be a crossover where a Kitsune from the Naruto universe ends up in the Fairytail world. Maybe the Kitsune has unique powers that are both ninja - like from Naruto and magical like in Fairytail. They could team up with the Fairytail guild members to fight a common enemy, like a dark wizard who is trying to steal the Kitsune's chakra for some evil spell.
One idea could be a gamer who gets sucked into the Fairytail world and starts to form a harem among the female characters. For example, he could use his gaming skills to impress them during battles. Maybe he masters a unique magic that no one in Fairytail has seen before, which draws the attention of Erza, Lucy, and other female mages. Another plot could be that he has to complete a series of in - game - like quests in the Fairytail world to win the hearts of the harem members. He might have to defeat a powerful dark guild while also dealing with the romantic interests of the girls.
Well, here's a plot idea. The male OC has a special connection to a magical artifact that is coveted by an evil force. He has to protect it while also trying to figure out why he has this connection. Also, he could be in a love triangle with two other characters in the guild, which adds a lot of drama to the story. Another idea is that he's the key to unlocking a hidden power within the Fairytail guild, but he doesn't know it at first and has to go through a series of trials to discover his true potential.
One idea could be to create an OC (Original Character) who has a unique multimagic ability that is related to the elements but in a different way than the existing characters in Fairytail. For example, instead of controlling fire, water, etc. directly, the OC can manipulate the energy within those elements. They could join Fairytail and face challenges that test their new abilities and their loyalty to the guild.
One great Samuel OC Fairytail fanfiction could be about the OC's journey to find their true magic within the Fairy Tail guild. They might start as an outcast and slowly earn the respect of the other members through acts of great courage and kindness.
One idea could be creating an OC who has a unique power related to time manipulation. They could be from a different dimension and end up in the Avengers' world. Another idea is an OC who is a master of ancient magic and teams up with Doctor Strange within the Avengers group. Maybe an OC that is a super - intelligent android created by a villain but has a change of heart and joins the Avengers.
You could create an OC for your Persona OC fanfiction who is an artist. This artist OC could use their art as a way to understand and even manipulate the Metaverse. For example, they might draw scenes from the Metaverse that give clues about upcoming events or hidden locations. Their art could also be a form of therapy for other characters who are struggling with their dual lives in the real world and the Metaverse.