In Harry Potter Holy Dragon Slayer fanfiction, who could be the main antagonist?

A powerful dragon - themed pirate could be the main antagonist. This pirate has a crew of dragon - like creatures and they are causing chaos across the seas. They have a grudge against Luffy for some reason, perhaps because Luffy has unknowingly entered their territory or stolen something valuable from them.

A powerful dark dragon that was once sealed away but has now broken free. It could have a vendetta against all dragon slayers, especially Gray.

There could be a group of pure - blood wizards who believe that dragons are beneath them and that Harry is tainting the wizarding world by associating with them. They would try to stop Harry from his dragon - related activities, and they might use underhanded tactics like casting spells on him or trying to get him expelled from Hogwarts.

Maybe a group of dark wizards who are jealous of the power of the dragon knights. They form an alliance to destroy the dragon knights and anyone associated with them, making Harry and his newfound friends their main targets.

It could be Voldemort still. Even with Harry having the power of a dragon god, Voldemort would be a major threat. He might be envious of Harry's new power and try to steal it for himself.

In some cases, it could be a jealous Hogwarts student. This student might be envious of Harry's special bond with the dragon. They could try to undermine Harry and the dragon's relationship, maybe by spreading false rumors or trying to get the dragon in trouble with the school authorities. This student could be working with some dark forces indirectly, as their envy makes them vulnerable to being influenced by the wrong side.

Perhaps a group of anti - dragon fanatics within the wizarding world could be the main antagonists. They see the dragon as a dangerous and uncontrollable creature and will do anything to get rid of it, even if it means going against Harry.

It could be another wizard who wants to use the dragon for evil purposes. This wizard might try to stop Harry from taming the dragon so that he can have it for himself.

Maybe it's an organization that believes the dragon's blessing is an abomination to the wizarding world's natural order. They see Harry as a threat and will stop at nothing to eliminate him and the power he has received. They could be a secret group within the Ministry of Magic that has its own radical ideas about magic and purity.

It could be an evil water mage who was once a student of the same master as Juvia but turned to the dark side. This antagonist would be jealous of Juvia's natural talent and would try to undermine her at every turn. He might use his knowledge of water magic to create dangerous illusions or floods to harm Juvia and those she cares about.