Who could be the main antagonist in a 'Mystic Falls meets Hope' fanfiction?

A great plot for 'Mystic Falls meets Hope' fanfiction could be a time - travel scenario. Hope accidentally gets sent back in time to the early days of Mystic Falls. There, she has to navigate the complex relationships between the founding families and the emerging vampires. She could also learn new magic from the witches in Mystic Falls at that time, which she then brings back to her own time to use against a new enemy. And, of course, she might form unexpected friendships or rivalries with the people she meets in the past.

A powerful sorcerer who has been consumed by despair could be the main antagonist. This sorcerer might see the mage of hope as a threat to his plan of spreading darkness and hopelessness across the world.

It could be the Hidden Leaf Village itself. If the village turns against Naruto through false accusations or unjust treatment, it becomes the force that drives him to the dark side. The elders or some of the more conservative ninja in the village who oppose Naruto's unorthodox ways could be the face of this antagonism.

It could be an envious classmate. Let's say Hope is really good at academics and is always getting top grades. This classmate, out of jealousy, starts spreading rumors about Hope, trying to isolate her from her friends and undermine her confidence.

It could be a powerful alchemist who has gone rogue and wants to use Naruto's chakra for some dark alchemy purpose.

There could be an ancient force that is awakened by the meeting of Harry and Hela. This force wants to destroy both of them because their combined powers could potentially stop it from achieving its goal of spreading chaos and destruction throughout all the realms. It would use all kinds of devious means to try and separate them and defeat them one by one.

Lex Luthor would be a great antagonist. He could see Superboy as a threat to his plans in Metropolis and try to find ways to discredit him or even eliminate him. Since Lois is a journalist, she might start to investigate Lex's actions against Superboy, which would put her in danger as well.

The World Government could be the main antagonist. They see both Luffy as a growing threat to their rule as a pirate and Dragon as a revolutionary. When Luffy and Dragon meet, the World Government might send their strongest agents like the Admirals to stop them from joining forces. The World Government's strict control over the world and their desire to maintain the status quo would put them in direct opposition to Luffy and Dragon.

It could be another powerful deity from either the Norse or the Christian pantheon who doesn't want Gabriel and Loki to team up. Maybe a more rigid and traditional angel who thinks Gabriel is consorting with the wrong crowd by interacting with Loki.

It could be an ancient and powerful vampire who has awakened from a long slumber. This vampire might see Alucard and Seras as a threat to his plans of ruling over all vampires.