A possible plot could involve Kagura being magically bound to a truth - telling spell. In her naked state (due to another part of the spell), she accidentally reveals her deepest secrets and feelings about the Fairy Tail guild and some of its members. This causes a stir within the guild as they deal with her revelations and also try to break the spell.
One plot idea could be that Kagura finds herself in an embarrassing situation in a magical forest. Maybe she loses her clothes due to a spell gone wrong. As she tries to find a way to get them back, she has to interact with various Fairy Tail characters, leading to humorous and heartwarming exchanges. For example, she might encounter Natsu who, in his typical clueless way, doesn't quite understand her distress at first but then tries to help.
Another idea is that Kagura is transported to an alternate dimension where the rules of modesty are different. She's initially embarrassed but then realizes she can use this situation to her advantage. She could team up with some Fairy Tail members who also end up in this dimension to find a way back home while learning about different cultures and magic in this new world.
It depends on how one looks at it. If the 'embarrassed naked' aspect is used in a way that is more about exploring vulnerability in a non - sexualized way, it could potentially be an interesting take on the character. However, more often than not, this kind of description in fanfiction can cross the line into being disrespectful to the original character design and the values of the Fairy Tail series. So, overall, it's likely not appropriate.
One plot idea could be that Mira gets caught in an embarrassing situation during a Fairy Tail event. For example, she accidentally casts a spell wrong and her clothes disappear just as an important guest arrives. Another could be that she is forced to participate in a contest where she has to show a hidden talent, but she's embarrassed about it. Maybe she has to sing in front of everyone when she thinks she's a bad singer.
Her character could also be developed through her problem - solving skills. Since she's in an embarrassing naked state, she has to figure out how to get proper clothing and deal with the social implications. This forces her to think on her feet and use her wits. She might discover new magical abilities or ways of using her existing powers that she didn't know before. Maybe she can create a temporary magical covering using her swordsmanship skills and her latent magic powers, which shows her resourcefulness.
Perhaps Wendy could be under a spell that makes her think she's invisible but in reality she's not, and she unknowingly walks around naked in front of the Fairy Tail guild. This would cause great embarrassment for her. The story could then focus on how she discovers the truth and how the guild members react in a humorous yet supportive way.
Another plot could involve a spell gone wrong that causes Erza to be in a state of undress in a public area in the Fairy Tail world. She then has to deal with the embarrassment while also facing a new threat that has emerged during this chaos. The story could focus on her regaining her composure and dignity while solving the problem.
One idea could be Juvia getting caught in an embarrassing situation during a Fairy Tail mission. For example, she might accidentally use her water magic in a way that makes her clothes wet and she feels extremely self - conscious, leading to some comical and heart - warming interactions with the other guild members as they try to comfort her.
A plot idea could be that Cana is dared to do something embarrassing in the Fairy Tail guild hall as part of a bet. She's hesitant at first but her competitive side takes over. However, things don't go as planned and she ends up in an even more embarrassing situation. Or perhaps she discovers a hidden power within herself while in an embarrassing state. She could be naked in a magical realm where she has to overcome her embarrassment to harness this new power and return to the normal world. This could lead to her becoming a stronger member of Fairy Tail.
Maybe in a fanfiction, Wendy is put under a spell that makes her think she's invisible but in reality, she's actually naked. She goes about her day in Fairy Tail, oblivious to her state, and gets into all sorts of embarrassing situations. For example, she might walk into a meeting of the guild leaders in that state. When she finally realizes, she's extremely mortified but her friends help her through it.
One possible plot idea could be Levy getting caught in an embarrassing situation during a Fairy Tail mission. For example, she might accidentally lose her clothes due to a magical mishap while trying to solve a riddle in an ancient ruin. This could lead to her being very embarrassed but also relying on her friends' support to get through it.
When writing this kind of fanfiction, it's important to be respectful. Avoid any sexual undertones. Instead of just presenting the 'embarrassed naked' situation, build a story around it. Maybe Kagura has been put in this situation by some magic gone wrong, and she has to rely on her friends to get out of it. Use her skills and her relationships within the Fairy Tail universe to drive the story forward. Also, keep in mind the age - range of the potential readers and make sure it's something that can be read by all fans of the series.