Voldemort or his Death Eaters could be antagonists. They might want to raid Gringotts to get powerful magical artifacts or gold to fund their dark deeds. Another option could be a group of corrupt wizards within the Ministry of Magic who see Gringotts as a source of wealth and power that they can control. They could try to undermine the Head Goblin and Harry Potter if they stand in their way.
Well, it could be a new dark wizard who emerges. This wizard is obsessed with ancient magic and believes that Gringotts holds the key to unlocking ultimate power. He tries to break into the bank's most secure vaults with the help of some dark creatures. Additionally, there could be a faction within the goblin society itself that is against any form of cooperation with wizards. They see the Head Goblin's relationship with Harry Potter as a betrayal of goblin traditions and will stop at nothing to end it and take over Gringotts.
It could be a powerful dark wizard who has a grudge against the goblins and wants to destroy Gringotts. This wizard might have been wronged by the goblins in the past, and now he's seeking revenge by trying to bring down the bank. He could be using his own army of dark creatures to attack Gringotts.
The goblin elders who oppose Harry's new - found ownership could be the main antagonists. They might be worried about losing their power and influence within Gringotts to a human, especially one as famous as Harry Potter.
Often, the goblins can be antagonists. If they have their own motives that conflict with Harry and Hermione's, like protecting a dark secret in the vaults or trying to take advantage of the situation for their own gain. Another possible antagonist could be a Death Eater who has infiltrated Gringotts to either steal something important or to ambush Harry and Hermione.
One idea could be that the Head Goblin discovers a long - lost magical artifact hidden deep within the vaults of Gringotts. This artifact has the power to change the balance of magic in the wizarding world. Another could be that the Head Goblin forms an unlikely alliance with Harry Potter to protect Gringotts from a dark wizard who wants to steal all the gold and magical items stored there. Or perhaps the Head Goblin has a secret past related to Harry's family, and this connection unfolds throughout the fanfiction.
It could be a young goblin who has just started working at Gringotts. He's full of enthusiasm but also a bit naive. Through his eyes, we can see the inner workings of the bank, the different vaults, and the various magical items stored there. Another option could be an older wizard who has a long - standing debt with Gringotts and is trying to find a way to pay it off without sacrificing his most precious magical possessions. Or perhaps a young witch who is an expert in ancient runes and is called in by Gringotts to help decipher some mysterious inscriptions found in one of the oldest vaults.
The goblins themselves could be the main antagonists. They are in charge of Gringotts and if they are greedy and corrupt, they would oppose any attempts by Harry to expose their wrongdoings that could lead to the bank's bankruptcy. They might try to stop Harry by using their magical skills and the defenses of the bank.
The main character could be a young Gringotts trainee who has always been overlooked but has a hidden talent for magic related to the vaults. Maybe they can sense the magical auras of different vaults and their contents, which is a rare ability. This character gets chosen as the champion unexpectedly and has to rise to the challenges that come their way, learning about their own power and the secrets of Gringotts along the way.
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.
One possible implication could be that Harry has access to unlimited wealth and resources. This would change his status significantly within the wizarding world. He could use the gold to fund various projects, like improving Hogwarts or helping out the less fortunate wizarding families.