In this fanfiction concept, Naruto could be given a special mission by some higher - up in his own world, like the Hokage or a sage. This mission could be related to restoring balance in other universes. So, he travels to Batman's world and realizes that bringing back his parents could be a huge step in restoring that balance. He then uses his ability to communicate with spirits (like he did with his father) and finds a way to return Batman's parents' spirits to their bodies.
Well, in fanfiction, anything can happen. Maybe Naruto has some sort of super - ninjutsu that can cross dimensions and time. He could use chakra in a unique way to bring back the dead. For example, he might find a way to access the same magic or energy that created the Lazarus Pit in Batman's universe and use his own ninja skills to manipulate it for resurrection.
The city of Gotham would also be affected. Batman has been a symbol of fear for criminals. Without his dark past driving him, there could be a power vacuum in the fight against crime. This might lead to an increase in criminal activity until new heroes or law enforcement methods emerge. Also, Batman's relationship with his villains would change. Some villains like the Joker might not have the same 'fun' without the brooding Batman they know.
In some fanfictions, Naruto might find a super - powerful jutsu or artifact. For example, he could discover a long - lost forbidden jutsu that has the power to bring the dead back to life. Or perhaps he stumbles upon a magical item during one of his adventures that is said to be able to revive the deceased.
If his parents were strict disciplinarians from a traditional ninja clan, Naruto might be more reserved and less of a prankster. He'd be more focused on following the clan's rules and traditions, and his drive to become Hokage could be more about upholding the family's honor.
His father could be Ash from Pokemon. Ash has had so many adventures and it would be interesting if he somehow ended up in the Naruto world and had a child with a Naruto - world character. His mother could be a random ninja who had a connection with Ash.
One possible scenario in such a fanfiction could be that Naruto's parents are preoccupied with their shinobi duties. They might be constantly on missions for the Hidden Leaf Village, leaving Naruto at home with caretakers who don't really pay him much attention. This could lead to Naruto feeling lonely and isolated, just as he did in the original story when he thought he had no family.
In this fanfiction, it could be that Naruto's parents were under some sort of mind - control. Some evil entity could have taken over their minds and made them feel hatred towards Naruto. Also, it might be related to a family secret or feud. There could be something in the family's past that made them believe Naruto was a stain on their family name, even though Naruto himself was innocent. It could also be a case of false information being spread around the village which made his parents believe lies about him.
The parents' relationship could also set an example for Naruto and Hinata. If Kushina and Hinata's mother had a strong, loving relationship, Hinata might be more inspired to be as loving and supportive in her relationship with Naruto. Similarly, Naruto could learn from his father's respect for Hinata's family and carry that forward in his relationship with Hinata.
If Naruto's parents were revived in fanfiction, the plot could change in many ways. For one, Naruto's character development might take a different turn. He could become more confident with his parents by his side. The power balance in the ninja world might also be affected. Enemies might think twice about attacking the Hidden Leaf with Minato and Kushina back. And Naruto could focus more on building a family and passing on his own legacy with his parents' guidance.
One possible storyline could be that Naruto grows up with his parents' love and training. He might become an even more powerful ninja at a younger age. Since Minato was a prodigy and Kushina had strong chakra, they could pass on their skills and knowledge early. Naruto could also have a different personality, more confident and less of an outcast as he has a loving family from the start.
One possible storyline could be that Minato and Kushina help Naruto train. They could pass on their unique jutsu and combat skills directly to him. This would make Naruto even more powerful at a much faster rate compared to in the original story.