One common theme is Hadou's self - discovery. In many fanfictions, she is exploring her powers and her place in the hero society. Another theme is friendship. For example, her bonds with classmates or other heroes are often explored, like how she might support or be supported by them.
One interesting concept could be exploring the darker side of the ninja world in a more in - depth way. For example, how the power of Dark Hadou might corrupt characters or change the power dynamics among the ninja villages. It might also involve creating new, morally ambiguous characters who are influenced by this dark power.
There is some. I've seen some on Wattpad as well. Some focus on how Nejire's bubbly personality might interact with Deku's more reserved and determined nature. It's really interesting to see how different authors imagine their relationship developing. For example, some might write about them meeting during a hero event and gradually falling for each other.
Naruto himself is often involved. He might be either tempted by Dark Hadou or have to fight against those who use it. Sasuke could also be a main character in such fanfictions. His quest for power could lead him to explore the Dark Hadou. And then there's Kakashi, who with his experience and knowledge, might be involved in trying to stop the spread of Dark Hadou.
You can start by looking on popular fanfiction websites such as Archive of Our Own. Just use the search function and type in 'izuku and nejire'. Browse through the results to find the ones that seem interesting to you.
One popular story might be 'Izuku and Nejire's Adventure'. It often has interesting character interactions where they go on quests together and develop a deep bond. The story may also include some sweet moments between them.
There are themes related to self - discovery. As they fall in love, they also discover new things about themselves. For Deku, it could be learning to be more confident in his personal relationships because of Nejire. For Nejire, it might be about finding a deeper purpose in her hero work through Deku. And of course, there are the typical romantic themes like first dates, confessions of love, and dealing with jealousy from other characters.
One interesting 'My Hero Academia Hadou' fanfiction is 'Hadou's Ascent'. In this fic, Hadou goes through intense training regimes that are really engaging to read. It shows her growth in a very detailed way.