Another plot could revolve around the relationships within the guild. For example, a fanfiction could explore a romantic relationship between two characters that was previously only hinted at in the original 'demon's tail'. This could add depth to their characters and show how their relationship affects the dynamics of the guild.
One idea could be a story where a new character with a unique magic joins Fairy Tail and has to prove themselves to the guild. Maybe they have a power related to time manipulation and use it to save the guild from a powerful demon's attack at a crucial moment.
Perhaps a fanfiction where a demon has a unique power that is needed by the Fairy Tail guild. The demon is initially reluctant but then realizes the importance of helping. They could form friendships within the guild and have adventures together, like going on a quest to retrieve a magical artifact.
Another plot could involve the female demon having a special power that Natsu needs to defeat a greater evil. Maybe she has the ability to control time briefly, and a dark wizard is trying to use this power for his own evil deeds. Natsu has to convince her to use her power for good and help him stop this wizard. Along the way, they develop a deep friendship and mutual understanding.
A really interesting plot could be that Naruto, as a demon, is wrongly accused of a series of attacks in the ninja world. He has to prove his innocence while also dealing with the prejudice and fear that his demon form instills in others. He might have to discover a way to temporarily suppress his demon form to gain the trust of those around him.
One idea could be exploring Batman's inner struggle against the influence of the Demon's Head. Maybe he has to resist dark temptations that the Demon's Head represents while still trying to protect Gotham. Another could be a story where Batman teams up with an unexpected ally, like a reformed villain, to take on the forces associated with the Demon's Head.
Another plot could involve Bardock having to adapt to the magic - based society of Fairy Tail. He might initially struggle with understanding how magic works, but then discovers a way to combine his Saiyan power with the magic there. For example, he could learn to use ki - based attacks in harmony with Fairy Tail's elemental magics. This would create a unique fighting style that surprises both his allies and enemies.
One idea could be a crossover adventure where characters from Fairy Tail and Negima team up to fight a common, powerful enemy. For example, they might face a dark wizard who has the ability to steal magic from both worlds.
One idea could be that the main couple from Fairy Tail goes on a honeymoon to a magical island. There, they discover a hidden ancient magic that they have to protect from villains who also find out about it. Another plot could involve them facing relationship challenges during the honeymoon, like misunderstandings due to magic gone wrong. For example, a spell makes one of them forget parts of their relationship, and they have to work through it to rekindle their love.
In a 'Fairy Tail WW2 Fanfiction', a possible plot could be that the guild discovers a hidden magical dimension that is somehow connected to the events of WW2. They enter this dimension to try and stop a dark force that is influencing the war from the shadows. Some of the characters could form alliances with real - life military personnel who are open - minded enough to accept their help. This would lead to interesting interactions between the magical and non - magical worlds during the war.
One idea could be exploring how the next generation of Fairy Tail wizards handle a new dark guild threat. They might have to combine the old and new magic techniques they've learned.
One idea could be that Luffy joins the Fairy Tail guild and his rubber powers amaze everyone. He might participate in a guild - wide competition and use his unique abilities to win in unexpected ways. For example, stretching to reach far - off targets or bouncing around the arena to dodge attacks.