The Naruto series has a very distinct world - building and set of values. It focuses on ninja skills, power - ups in a more acceptable ninja - like way, such as Sage Mode or Tailed Beast Mode. A 'transform into sex demon' concept is not in line with what the series represents, and most likely, official or well - respected fan works would not explore this.
There might be. Some fanfictions could have Naruto transform in a way that is symbolic of his connection to Hinata. Maybe he gains a new ability that is related to Hinata's unique skills or family traits. This would not only be a creative way to develop their relationship in the fanfiction but also a way to explore new aspects of the Naruto universe.
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.
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.
Well, if Naruto transforms into a Pokemon, it could be a really interesting change. Maybe he turns into a Charizard. Naruto's determination and willpower would translate well into Charizard's fierce nature. He could fly around the Pokemon world or his own world, using his fire - breathing abilities to fight off enemies. And his ability to form bonds, like he did with his friends in the Naruto series, could also apply to how he interacts with other Pokemon.
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.
If Naruto transforms into Hinata, his relationship with Sasuke might change. Sasuke might see a different side of Naruto, a more timid and gentle side like Hinata's. And when he's Neji, his relationship with the Hyuga clan could be different. He might be more involved in their internal affairs as Neji was. Also, his relationship with Shikamaru could be affected as he takes on Neji's more serious and duty - bound attitude.
Their relationship could start with Hinata being curious about the demon king Naruto. As she gets closer to him, she discovers the pain and loneliness behind his demon exterior. Hinata's empathy draws her closer to Naruto, and he starts to rely on her for emotional support. This mutual dependence could gradually transform into a deep, loving relationship as they face different challenges together in the fanfiction world.
One possible plotline could be Naruto's inner struggle with his new 'demon' side while still maintaining his love for Hinata. Maybe his demon powers make him more protective of her in a way that's different from his normal self.