Who could be the antagonist in 'Harry Potter Saves a Young Goblin' fanfiction?

It could be a dark wizard who has a vendetta against goblins. This wizard might see goblins as a source of power or wealth and wants to enslave them. So when Harry tries to save the goblin, this dark wizard becomes the main obstacle.

Well, perhaps the young goblin is in danger from some dark wizards who want to use its unique magical abilities for evil. Harry Potter, being the hero he is, stumbles upon the situation and uses his skills and magic to fend off the bad guys and save the goblin. Maybe he discovers the goblin has some information crucial to the wizarding world's safety too.

It could be some dark wizards who want to use the centaur's parts for potions. They might be following some ancient, dark magic recipe that requires centaur hair or hooves. So they hunt down the centaur, but Harry gets in their way.

It could be an ancient dark magic artifact. The artifact has a hold on Bellatrix, and in a way, it's the 'enemy' that Harry has to defeat to save her. The artifact might be trying to use Bellatrix to carry out some dark plan, like opening a portal to a world full of dark creatures. Harry has to figure out how to break the connection between Bellatrix and the artifact while also fending off the artifact's attacks.

It could be some of the pure - blood wizard families who have always looked down on goblins and consider them as inferior beings. They might oppose Harry's attempts to defend the goblin because it goes against their traditional views of the wizard - goblin hierarchy.

Well, perhaps Harry stumbles upon a goblin in a dangerous situation, like being trapped by dark wizards who want to steal the goblin's magic artifacts. Harry uses his skills and spells to fend off the bad guys and rescue the goblin.

It could be a dark wizard who has his eyes on Cintra's powerful magical artifacts. He wants to use them to gain more power and is willing to destroy Cintra to get them.

It could be a rogue Death Eater who has escaped from Azkaban. This Death Eater might be desperate to regain his power and believes that unicorn blood will give him the strength he needs. So he sets out to capture a unicorn in the Forbidden Forest, which is where Harry comes in to stop him.

It could be a powerful dark wizard who has a grudge against the goblins. Maybe he wants to steal the goblin's vast treasures and is willing to get rid of the Goblin King to do so.

It could be that the Goblin King's magical artifacts are being stolen one by one, and this is weakening his realm. Harry Potter gets wind of this and decides to help. He teams up with some of his Hogwarts friends like Hermione and Ron. They use their combined knowledge of magic and spells to track down the thieves and return the artifacts to the Goblin King, thus saving his kingdom.