Who could be the main antagonists in 'Harry Potter goes to Marauders era fanfiction'?

One possible main antagonist could be the headmaster of the killer school. If the school is a place that values strength and ruthlessness, the headmaster might be a tyrant who enjoys seeing students struggle and fail. He or she could be constantly setting up dangerous situations for Harry just to test him.

Perhaps some students who are jealous of Harry's fame could be antagonists. They might try to undermine him during training exercises.

Obviously, Harry himself is a very popular character in these fanfics. After all, he's the one who has traveled to the Marauders era. Then there are the Marauders - James, Sirius, Remus, and Peter. Fans love exploring their relationships and personalities in more depth. Lily Evans is also quite popular as she's Harry's mother. Her interactions with Harry and how she develops in this different scenario are often a big draw for readers.

There might be an ancient evil entity that has been trapped within the university grounds for centuries. When Harry arrives, it senses his power and tries to use him to break free. This entity could manipulate other students and staff to achieve its goal, making it a very dangerous and complex antagonist.

The main antagonists could be those who don't want Harry to receive a proper Hogwarts education. Maybe some dark wizards who fear that Harry will become too powerful if he goes through the Hogwarts training. So, they plot to keep him away from Hogwarts.

The main characters are Harry Potter for sure. He's the one who is reborn into the Marauders era. Then there are his parents, James and Lily. They are important as Harry gets to know them in a whole new way. The Marauders are also central. Sirius, with his wild and loyal nature, Remus with his werewolf secret, and Peter, who later betrays them in the original story. Their relationships with Harry add a lot of depth to the story.

A great plot idea could be Harry getting involved in the Marauders' pranks but also using his experiences to guide them towards more responsible magic use. He could also be a key figure in uniting different groups in the wizarding world during that time. Since he has a different perspective, he might be able to bridge the gap between pure - bloods, half - bloods, and Muggle - borns much earlier, which could have a huge impact on the future and the fight against Voldemort.

The Thalmor could be great antagonists. Their strict control over magic and their anti - human beliefs could put them at odds with Harry. They might see his different form of magic as a threat to their power in Skyrim.

One possible antagonist could be a corrupt wizard in a high - ranking position in the Ministry of Magic's financial department. This wizard might be trying to cover up his misdeeds and would see Harry as a threat to his scheme.

A great plotline in such fanfics is when Harry has to deal with the time - travel paradoxes. Since he's in the Marauders era, any change he makes could have a huge impact on his own future. He might be hesitant to do too much at first. Also, his relationships with the Marauders are fascinating. He could become like a mentor figure to them in some ways, teaching them things he learned from Dumbledore. And the whole idea of him being in a world where Voldemort is still rising but in a different stage is full of potential for exciting story development.