One idea could be that the fallen star is actually a powerful wizard from a different dimension who has lost their powers during the fall. They end up in the Fairy Tail world and have to team up with the guild members to regain their powers and find a way back home. Another plot could involve the fallen star being a magical object that holds a great secret, and Fairy Tail members race against an evil guild to discover and protect it.
A possible plot for a 'fallen star fairy tail fanfic' could be that the fallen star is a symbol of an ancient prophecy. The Fairy Tail guild discovers that the star's fall signals the coming of a great danger or a powerful magic that could change the world. The guild members then embark on a journey to find out more about the star, its origin, and how to prevent the prophecy from coming true. Along the way, they face various challenges and meet new characters who are either helping or hindering their quest.
A really interesting plot could be a time - travel scenario. A Fairy Tail wizard somehow ends up in the past of the Star Wars universe, during the Clone Wars perhaps. They could get involved in the conflict, befriend some of the Jedi or even help Anakin Skywalker avoid his fall to the dark side. In return, the Jedi could teach the wizard some new skills related to the Force. Or, a Star Wars character could be transported to the Fairy Tail world and has to adapt to the magic - based society. They could use their technological knowledge to help Fairy Tail in a time of crisis, like when facing a powerful dark guild.
One idea could be to focus on a character who discovers a new and rare Star Dress form. For example, Lucy could find a Star Dress that has powers related to an ancient celestial spirit. This would lead to her having to learn how to control it and facing challenges along the way as she tries to master the new powers.
A 'Fallen Star' in a Harry Potter and Fairy Tail fanfic could be a very interesting concept. It might refer to a character who was once highly regarded but has fallen from grace. In the context of Harry Potter, it could be a wizard who has turned to the dark side, perhaps influenced by the Death Eaters' ideology. In Fairy Tail, it could be a mage who has lost their power or been exiled from the guild. The fanfic could explore their journey to redemption or further descent into darkness.
One plot idea could be Aquarius getting lost in the human world. She accidentally gets separated from the Celestial Spirit World and has to find her way back. Along the way, she teams up with some of the Fairy Tail members who are initially skeptical of her but then realize she's not as bad as they thought. Another idea is that Aquarius discovers a hidden power within herself that she didn't know she had. This power could be related to a long - lost magic that was once prevalent in the Celestial Spirit World. It could put her in danger as there are forces that want to control this power.
Well, you could write a 'a fairy'a tail fanfic' about a time - travel adventure. Maybe the characters go back in time to prevent a great disaster that was hinted at in the original series. Or perhaps a story where the Fairy Tail guild has to team up with their arch - enemies to face a common, much greater threat. And a simple but interesting idea could be a day - in - the - life story of one of the guild members, showing their normal routine as well as some unexpected events.
You could write a 'Fairy Tail Fanfic' where the magic system is completely different. For example, instead of having different types of elemental and non - elemental magic, there's only one type of magic but different levels of mastery. Or a fanfic that focuses on the relationships between the guild members in a romantic aspect. Like a love triangle between Gray, Juvia, and a new character.
One idea could be that Lucy discovers a new, extremely powerful star dress that has a mind of its own. It tries to take over her actions, leading to some chaotic and dangerous situations for her and the Fairy Tail guild. Another plot could involve Lucy's star dress being linked to an ancient prophecy. As she wears different star dresses, she uncovers parts of the prophecy that lead her on a quest to save the magical world.
A cool plot could involve Naruto and Natsu being somehow related. Maybe they share a common ancestor from a long - ago time when the two worlds were more connected. As a result, they both have similar powers but in different forms. This could lead to them teaming up to fight a common enemy that threatens both their worlds. The Fairy Tail mages could teach the Naruto characters about different types of magic, and in return, the Naruto characters could teach them some ninja skills.
One idea could be that Naruto and his friends are transported to the Fairy Tail world. They could join forces with Natsu and the gang to fight a common enemy, like a powerful dark wizard who has the ability to control the Nine - Tailed Fox. Another plot could involve the sharing of magic and ninja techniques between the two groups. For example, Naruto teaching some Fairy Tail members basic ninja moves while they teach him some magic spells.
One idea could be that Naruto characters end up in the Fairy Tail world through a magical portal. They could then team up with Fairy Tail members to fight a common enemy. For example, Naruto and Natsu could combine their powers of fire - Naruto's Fire Style jutsu and Natsu's Fire Dragon Slayer magic.