Who could be the antagonists in 'hermione saves the potters fanfiction'?

Well, it could be that Hermione uses her time - turning device to go back in time and warn the Potters about Voldemort's plan. Maybe she disguises herself and manages to get into their hiding place, then uses her magic skills to set up powerful protective spells around them that Voldemort can't break through.

It could be some water - dwelling dark creatures. Maybe mermaids with a malicious streak or some sort of lake - bound demons that were awakened when Hermione got too close. They might see her as an intruder and want to harm her, which is why Harry has to save her.

One possibility for the antagonists could be a rogue group of ninjas who are after the power of the Sound Four. They might see the Sound Four as a means to gain more influence in the ninja world.

Well, it's possible that a powerful and evil pirate lord could be the main antagonist in 'hermione is a pirate fanfiction'. This pirate lord might control a large part of the seas and sees Hermione as a threat to his dominance. He could have a large fleet and many ruthless henchmen. He might try to capture Hermione to either make her join his crew or to simply get rid of her because she is disrupting the order he has established in the pirate world.

The Ministry of Magic itself could be an antagonist. If they don't approve of Hermione's adoption due to her age or some bureaucratic reasons, they could try to take the baby away. They might think she's not fit to raise a child, which would create a lot of conflict in the story.

One possible antagonist could be Orochimaru. He might be interested in Kim's unique skills and gadgets for his own evil experiments. He could set a trap for her and Naruto would have to save her from Orochimaru's clutches. Another could be Drakken. He might team up with some ninja villains, like the Akatsuki members, in order to achieve his own goals. Naruto and Kim would then have to face this combined force.

Danzo could be a main antagonist. He was always paranoid about the Uchiha clan's power and was involved in many of the events that led to their downfall. In a fanfiction where Naruto is trying to save the clan, Danzo would likely oppose Naruto's efforts as he sees the Uchiha as a threat to his own power and the village's stability in his own twisted way.

It could be Team Rocket. They are always causing trouble for Ash, and it would make sense for them to be the ones behind Ash's predicament in this fanfiction. They might have a new evil plan to capture Ash and Sceptile comes to the rescue.

Well, obviously Snape is a main focus. His motives, his actions, and his complex personality are usually explored in depth. Then there are the Potters - James, Lily, and Harry (even as a baby). Their relationship with Snape, especially Lily's influence on Snape, is often a central part of the story.

It could be some traditionalist wizards who don't like the idea of Hermione and Teddy leaving the wizarding world and living among muggles. They might try to bring them back by force or create problems for them in Forks. Another possibility is some local dark forces in Forks that are threatened by Hermione's magic and Teddy's abilities.