Writing sexual fanfic, especially when it involves non - consensual or inappropriate use of characters, is not appropriate. It goes against ethical and respectful creation of fan - made content.
I don't know exactly. It could depend on the specific manga universe or storyline. Maybe you can search through popular manga forums or fan communities for the answer.
A common theme is the power of their combined strength. Tanjiro has his own set of skills and Mitsuri has hers. Fanfics often explore how they use their combined powers to defeat powerful demons. Additionally, the theme of hope is often present. Their relationship gives them hope in the dark world of demon slaying, and they inspire others around them with their positive attitude and connection.
One great 'tanjiro x mitsuri fanfic' is 'A Bond Beyond the Demon Slayer Corps'. It really delves into their relationship, showing how their different personalities complement each other. Tanjiro's kind - hearted nature and Mitsuri's energetic and affectionate side create a really interesting dynamic in the story.
It could be Voldemort. Voldemort might use Harry's love as a weapon against him. He could either kill her or turn her against Harry. Another possibility is Draco Malfoy. Maybe Draco tricks Harry's love into thinking he's a better choice. Or it could be a new, unknown dark wizard who targets Harry through his love.
Yuki would definitely be affected. She has a close relationship with Zero, and his loss of control could put her in danger. Also, she would be emotionally distraught seeing Zero in such a state.
Maybe he starts to train with one - armed techniques. He could learn from other one - armed ninjas if there are any in the fanfiction world. His friends would also play a big role. They might encourage him to keep going or help him in his training.