There might be a group of interdimensional hunters. They target beings who cross into alternate dimensions without permission. Peter, being an unexpected visitor in this new dimension, becomes their target. They are highly skilled and have advanced technology or magic that makes them difficult to defeat. They believe that Peter's presence could disrupt the balance of the alternate dimension.
In the alternate dimension, there could be a dark entity that feeds on the life force of the dimension's inhabitants. When Peter arrives, it senses his different energy and tries to consume him. But once it realizes that Peter has the potential to stop it, it turns its full attention to destroying him first before it continues its reign of terror in the dimension.
One potential antagonist could be a rogue ninja who also has aerokinesis but uses it for evil. He might be jealous of Naruto's natural talent and try to undermine him at every turn. Another could be a powerful sorcerer from a far - off land who has come to the Naruto universe specifically to find someone with aerokinesis to either steal their power or use them as a tool. There could also be a group of anti - ninja who see Naruto's new power as a threat to their plans of overthrowing the ninja system and they try to eliminate him.
One interesting one could be 'Peter Parker's Multiverse Adventure'. In this fanfic, Peter Parker gets accidentally pulled into an alternate dimension where he meets different versions of himself. It's full of action and self - discovery as he has to figure out how to get back to his own dimension while dealing with the new challenges and powers of his alternate selves.
One idea could be that Peter discovers he has superpowers unique to this alternate dimension. For example, he might be able to control time in a different way than in his own world. Another plot could involve Peter meeting alternate versions of his friends and family, and having to deal with the differences in their personalities and relationships. Maybe in this dimension, his best friend is his enemy, and he has to figure out how to change that.
Perhaps Orochimaru could still be an antagonist. In this fanfiction, he might be jealous of Naruto's new god - like gaming powers and try to steal them for his own experiments.
There could be a jealous fellow ninja from within the village who feels that Naruto is getting too much attention for his blade - mastery. This ninja could turn against Naruto and become an antagonist, perhaps even teaming up with external forces. Also, an ancient evil entity that was sealed away long ago might be awakened by the power of Naruto's blade and seek to destroy him and the village to regain its freedom.
It could be some of the hospital's board members who might not approve of their relationship and Cameron's pregnancy while working at the hospital. They could try to make things difficult for the couple.
Well, there could be an evil scientist in the fanfiction. This scientist might be researching the power of hypnosis on Pokemon trainers and sees Iris as a perfect test subject. They would use their advanced technology and knowledge of Pokemon behavior to hypnotize her. Also, a powerful psychic - type Pokemon that has gone rogue could be an antagonist. It might hypnotize Iris to do its bidding, like stealing other powerful Pokemon or causing chaos in Pokemon battles. And don't forget about a group of treasure hunters who want to use Iris's hypnotized state to find a hidden treasure that only she knows the location of through her adventures.
There could be new antagonists created specifically for this fanfiction. Maybe some other ninja from a far - off land who are jealous of Naruto's power. They could come to the Hidden Leaf Village to challenge Naruto and steal his speed - related secrets.
Cell could also be an antagonist. He has an interest in powerful Saiyan genetics. The baby, being related to Goku, would be of great interest to him. He might try to absorb the baby to gain even more power, creating a big conflict for the heroes to deal with.
There could be a new vampire hunter in town. This hunter could target Stefan and Elena because of their relationship. He might believe that their union will create a more powerful vampire line and wants to stop it before it's too late.