In this fanfiction, Harry might find out that his ownership of Gringotts is part of a much larger prophecy. As the owner, he has to protect the bank from those who would use its vast resources for evil. He could also use the bank's wealth to improve the living conditions of magical creatures and underprivileged wizards, while facing opposition from the traditional pure - blood families who don't want to see such changes.
One possible plot could be that Harry discovers he has some ancient claim to Gringotts. He then has to deal with the goblin politics and power struggles within the bank. Maybe he tries to reform some of the old and unfair practices at 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.
In this fanfiction, perhaps Voldemort is after some powerful magical artifacts stored in Gringotts. Harry, being the hero, steps in. He might have to face various challenges like dark magic traps and dangerous creatures inside the bank while trying to keep it safe. He could also form an alliance with the goblins, who are initially skeptical of him, but then see his determination to protect their precious bank.
Perhaps in this fanfiction, Harry Potter becomes the King of Gringotts due to some prophecy or a special gift he has. As the king, he could start to reform the goblin - wizard relations. He might introduce new policies in Gringotts that benefit both wizards and goblins, which would lead to a whole new set of adventures and challenges as he tries to balance the different interests.
Perhaps the fanfiction focuses on a heist at Gringotts to steal this special weapon. The characters might face all kinds of obstacles, like the complex security systems in Gringotts, which include things like the dragon guarding the vaults and the magical spells protecting the treasures. They would need to use their unique skills and knowledge of magic to get past these barriers.
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.
A plot could involve a competition among different Gringotts employees to become the 'Gringotts Champion'. The winner would get a special privilege, like access to a long - sealed vault that is rumored to hold great power. A young and ambitious wizard working at Gringotts decides to enter the competition. He discovers that there are dark forces at work trying to rig the competition in their favor. With the help of Harry Potter, who he meets by chance, they expose the conspiracy and ensure a fair competition.
It could also be a strategic move. Gringotts is a highly secure place. By buying it, Harry could ensure the safety of important magical artifacts or secrets. He could use it as a base to store and protect things that are crucial for the future of the wizarding world, like ancient spells or prophecies.
In this fanfiction, perhaps Harry decides to renovate Hogwarts. He could add new sections for different types of magic study, like a special wing for time - traveling magic research. Also, as the owner, he'd have to deal with the political aspects of the wizarding world trying to influence the school's curriculum.
One possible motive could be to stop Voldemort from getting his hands on some crucial dark magic item stored in Gringotts. Harry might think that by destroying it, he can prevent Voldemort from getting more power.
Well, in the fanfiction, Fem Harry Potter might find that her vault has been tampered with. Since she's a female, she may be more perceptive to certain details that the male Harry wouldn't notice. She could then start an investigation right there in Gringotts, interrogating the goblins and using her intuition to figure out who was behind the tampering. This could lead to a mystery - solving adventure within the bank.