Well, it's not ethical at all. Fanfiction should generally stay within the boundaries of respect for the source material. When it comes to creating erotic content related to a character, it not only violates the moral code but can also be offensive to the fans who love the character for its original qualities and the story it belongs to. It can also potentially cause issues with the copyright holders of the original work.
One alternative could be creating non - sexual, friendship - based fanfic. For example, stories about Aoi Asahina's adventures with other characters in a more innocent and positive context. Another option is to write character - study fanfic, exploring her personality, dreams, and growth without any sexual elements.
I'm not sure of a specific aoI asahina muscle fanfic off - hand, but you can try looking on fanfic websites. Search for tags related to his name and'muscle' to find relevant stories.
A really interesting aoI asahina muscle fanfic could explore the backstory of how he got interested in building muscles in the first place. It could talk about his early days, the inspiration that led him to start working on his physique, and how he gradually developed his current muscular form over time.
There is a fanfic called 'Natsume's Journey'. In this story, it delves deep into Natsume's growth and development. It has detailed descriptions of her relationships with other characters, making it a very immersive read.
You could look for fanfics that focus on the emotional bonds between the characters. For instance, stories about Asahina Masaomi and Ema's sibling - like relationship development, how they support each other through difficult times.
Another theme could be adventure. They are often put into various dangerous or exciting situations in fanfic, which showcases their courage and the bond between them. For instance, they might embark on a quest to save their world from a mysterious evil force. This not only tests their relationship but also allows for the development of their individual characters in the context of the story.
An 'evil' Valt Aoi fanfic could explore his relationships in a different light. His friends might be shocked and have to deal with this new side of him. They would likely try to bring him back to his normal self. For example, Shu could try to reach out to him, but Valt, in his evil state, might reject him and see Shu as an enemy.
One common theme is friendship. Yusaku's relationships with other characters are often explored in fanfics, showing how he bonds with different people.
First, study Asahina Natsume's character traits. Observe how she behaves, talks, and reacts in the original work. This will help you create a believable version of her in your fanfic.