One possible fanfiction idea could be that Hinata discovers Naruto has a half - demon side that he's been hiding. This could lead to a lot of interesting character development. Hinata, being the understanding person she is, might help Naruto come to terms with this part of himself. It could also introduce new powers and abilities for Naruto, and perhaps a new level of relationship between the two.
One interesting plot point is that the village elders are against Naruto and Hinata's relationship because of Naruto's half - demon nature. They fear that it will bring danger to the village. However, Naruto and Hinata are determined to stay together and prove that their love can overcome any prejudice. Also, Naruto's half - demon form could attract the attention of other powerful forces outside the village, either as a threat or as a potential ally, and they have to navigate these situations.
One common theme is the struggle for identity. Naruto, with his half - angel half - demon nature, often has to figure out where he belongs. Another theme is power control. Balancing the angelic and demonic powers can be a huge challenge.
In this fanfiction, Naruto's development as a demon would mean he has to face the prejudices of the village all over again. This would make him more determined to prove himself. Hinata would develop her own skills in order to protect Naruto. She might also develop a new sense of leadership as she stands up for Naruto against the village's doubts. Naruto would learn the value of having someone like Hinata in his life and would strive to be a better version of himself, both as a demon and as a person who is part of the village.
One common theme is the struggle with identity. Since Naruto has half - demon blood, he has to figure out who he really is, whether he's more human or more demon. Another theme is power. The half - demon aspect usually gives him some unique powers, and he has to learn to control them.
One possible plot could be Naruto discovers his half - angel, half - demon fox nature during a life - threatening battle. His angel side gives him the ability to heal and purify, while his demon fox side provides immense power. He struggles to balance these two sides as he faces powerful enemies who are either attracted to or threatened by his unique nature.
It could be a powerful ninja from another village who is jealous of Naruto's half - demon half - god powers. He might see Naruto as a threat to his own village's dominance and try to eliminate him.
In some fanfictions, Demon Naruto's character may become more isolated at first. His demon nature makes him feel like an outcast, even from his friends. But Hinata's presence gradually changes him. She gives him the acceptance he needs, and this causes his character to soften. He starts to trust more and rely on her, which is a big change from his initial guarded state.
The plot could involve Naruto being turned into a demon through some dark magic. Hinata, being in love with Naruto, refuses to give up on him. She decides to train hard to be able to protect Naruto from those who want to destroy him. Along the way, they discover a way to reverse the demon transformation, but Naruto has to make a choice between his newfound power and becoming normal again.
Their relationship would likely become even more intense. As half - demons, they would have to rely on each other more for support in dealing with their new forms and the challenges that come with it. They might also develop a deeper understanding of each other's insecurities.