Naruto's moral compass would be greatly affected. Zeref has a much darker view of the world compared to Naruto. So, Naruto might start to see things in a more cynical way. He could view his old enemies as mere pawns in a bigger game. This would lead to a lot of internal conflict as he tries to reconcile his old self with this new Zeref - influenced mindset. His friends would try to pull him back from the brink, but it would be a difficult battle.
Well, Naruto would probably be a very different character. Zeref has a dark and complex nature. Naruto might grow up with a different view on power and life. He could be more conflicted between his natural heroic tendencies and Zeref's influence which often leans towards the darker side of magic and existence.
Kiba could end up having a whole new set of skills or abilities as a girl. In the Naruto world, different genders might have different natural affinities for certain types of jutsu. So, as a girl, Kiba could discover she has a better connection to, say, healing jutsu or some other form of ninjutsu that she didn't have before. This could be really interesting as it would change her role in the team and in the village.
Yes, there might be such a fanfiction. It could be about Naruto somehow being connected to Zeref. Maybe Naruto gets transported to the world where Zeref exists and has to deal with Zeref's dark magic and his plans. It could also be a crossover where their powers combine in some unexpected ways, like Naruto's chakra interacting with Zeref's magic in a new form of combat.
In a Natsu joins Zeref fanfiction, one possibility is that Natsu could initially be conflicted. He has always seen Zeref as an enemy, but perhaps there's a common goal they discover. For example, they might find out about a greater evil that threatens the entire magical world. Natsu's fiery nature could be used in a new way when combined with Zeref's dark magic. This could lead to a very different power dynamic compared to what we see in the original Fairy Tail story.
Well, one possibility is that Naruto would be extremely protective. He has always cared for Hinata in some way, and with her as a baby, he'd likely take on a very nurturing role. Maybe he'd try to find a way to turn her back, or he'd just enjoy taking care of her like she was his own little sister or something. He could introduce her to all his friends in the village as his 'new little friend' and they'd all be super curious about how this happened.
Well, one possibility is that Naruto loses control of his new demon form and goes on a rampage. His friends would be shocked and try to bring him back to his senses. They might use their unique abilities to try and calm the demon - Naruto down.
Well, one possibility is that Naruto could gain enhanced senses like a true kitsune. He might be able to smell danger from afar or hear the faintest of whispers. This new form could also give him an air of mystery, making his friends and foes alike wonder what he's truly capable of now.
In terms of the story's development, it could lead to a whole new arc. Naruto's transformation into a baby girl could be a sign of a greater threat to the ninja world. It might be related to some ancient curse or a new enemy's plot. And as he tries to figure out how to turn back, he would have to rely on his friends and his own inner strength in a different way than before.
One possible plot could be that Zeref has a new target in the Naruto universe. Naruto discovers this and decides to confront him. At first, Naruto is outmatched as he doesn't understand Zeref's magic. But then he starts to analyze it during their battles and figures out ways to counter it. Meanwhile, Zeref is intrigued by Naruto's never - say - die attitude and chakra. The plot could also involve other characters from both universes getting involved, either to help or to cause more chaos.
Perhaps the plot could start with Naruto finding out he is Zeref's brother. This revelation could shatter his understanding of his identity. He then embarks on a journey to learn about his past and Zeref's motives. As he delves deeper, he discovers secrets about the two worlds (Naruto's and Fairy Tail's) that are intertwined. He has to deal with the conflict between his loyalty to his new - found family (Zeref) and his own moral compass. Maybe he tries to find a way to save Zeref from his own self - destruction while also protecting the people of both worlds from Zeref's potential threats.