Well, in the fanfiction, the sealed hatred could transform Naruto into a more complex character. He might start to question his own motives and actions more deeply. Since the hatred is sealed within him, he may feel like he's constantly at war with himself. This internal conflict could lead to him making different decisions than he would in the original story. He could become more hesitant in his actions, always considering the potential influence of the sealed hatred on his choices, which is a big departure from his more straightforward and impulsive nature in the main Naruto storyline.
It might also make him more cautious in a way. Since Minato's power is now a part of him, he has to be careful not to misuse it or let it get out of control. So, he may take more time to think before acting, which is a change from his usually impulsive nature.
The Chimera concept can make Naruto more complex. If he has chimera powers, he may become more cautious as he doesn't fully understand them at first. He might also be more isolated as others may be afraid of his new powers.
Naruto's character could become more patient. With immortality, he has all the time to wait for things to develop. For example, instead of rushing into a fight, he might wait for the perfect moment. Also, his view on life and death would change. He would no longer fear losing his loved ones in the same way as he knows he can't die. This could make him more empathetic towards those who are afraid of death.
He becomes more aggressive. His friendly nature is gone and he's quick to lash out.
Well, Naruto might become more mysterious. Since Gaster is an unknown and rather enigmatic entity, Naruto could start having strange thoughts or powers that he doesn't fully understand at first. He might seem more withdrawn as he tries to figure out what's going on inside him, and his normal cheerful and straightforward personality could be clouded by the presence of Gaster.
It can simplify the plot. Without Naruto's internal struggle with hatred, he may make more rational decisions, which can speed up the resolution of conflicts in the story.
The 'godlike hanyou' idea often makes Naruto more of an outcast in some fanfictions. People might be afraid of his new powers or misunderstand them. This can lead to Naruto feeling lonely at times, but it also makes him more determined to prove himself and show that his powers can be used for good. He has to learn to control his hanyou side and show others that he's still the same Naruto at heart, just with added abilities.
In fanfiction, the dark chakra can make Naruto more brooding. Instead of his usual optimistic self, he becomes more withdrawn as he struggles with the new power. For example, he may question his own identity and whether he can still be the hero everyone expects him to be.
In fanfiction, the 'feral child' concept can make Naruto more instinct - driven. He might rely more on his gut feelings rather than traditional ninja training. For example, instead of following a set jutsu sequence, he might improvise based on his immediate senses. This can also make him more of an outsider in the village. His different behavior and way of thinking might not be easily understood by the other villagers, which could lead to more conflict or misunderstanding. But it also gives him a unique charm as he is not the typical well - behaved ninja - in - training.
It changes his fighting style completely. He no longer relies on his shadow clones and Rasengan. Instead, he uses his cold powers to freeze opponents or create ice barriers. This makes him a more strategic fighter. Also, his relationships with his friends might change. They could be a bit afraid of his new power at first, but as the story progresses, they learn to accept it. For example, Kakashi might have to train him differently to help him control this power.