Who could be the main antagonists in a 'Harry Potter King of Magical Creatures' fanfiction?

The plot could involve Harry Potter having a special connection with magical creatures that no one else has. He might discover a new type of magical creature and learn its secrets, which could help him in his fight against the dark forces.

Neville would also make an excellent main character. He has a natural affinity for plants, and magical creatures are not that far off in the wizarding world. He could be the one to discover a new way to care for ailing magical creatures, perhaps using his knowledge of herbology. For example, he might find a plant that can cure a disease that's been affecting the unicorns in the forest.

The Death Eaters could be one group of antagonists. They might see Harry's newfound power and position as the King of Valyria as a threat to their plans for wizarding world domination. So they try to stop him from fully realizing his potential in Valyria and bringing back any new magic or alliances that could defeat them.

The pure - blood supremacist wizards who don't want a half - blood like Harry as the king could be the antagonists. They might try to undermine his rule and spread false rumors about him.

One main antagonist could be the existing power - hungry rulers in Essos. They would see Harry Potter as a threat to their rule and try to eliminate him. Another could be dark magic cults in Essos that oppose any form of new leadership or change that Harry might bring.

There could be a magical creature that has been corrupted by dark magic in the North. This creature sees Harry Potter as a threat to its existence and will do everything it can to drive him out or even kill him. It might be very powerful and difficult to defeat, forcing Harry to find new ways to use his magic.

A likely antagonist could be a rogue wizard who has already made a deal with the demons and doesn't want Harry interfering. This wizard could be using the demons to carry out his revenge on the wizarding world for past wrongs. There might also be a powerful demoness who wants to use Harry as a pawn in her own power struggle within the demon realm. She could initially pretend to be an ally but then turn on him. And finally, a group of anti - Muggleborn extremists who believe that Harry's connection to the demons is a sign of impurity and try to eliminate him, thinking they are protecting the wizarding world's purity.

The pure - blood supremacist families could be the main antagonists. They might see Harry as a threat to their traditional ways of running Hogwarts. They would oppose his new rules and reforms that aim for a more inclusive and equal school. For example, they could try to undermine his authority by spreading false rumors about him among the students and their families.

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.

It could be other members of the royal family who see Harry as a threat to their power or position. They might try to undermine him and prevent him from claiming his rightful place as king.