The goblin might be helping Harry because Harry once did a favor for the goblin's family. In the fanfiction, the goblin could be an expert in ancient magic spells that have been long forgotten. He could teach Harry these spells, which would give Harry an edge in the fight against the forces of evil. For example, a spell that can turn the dark wizard's own magic back on them.
The goblin could start off as a mysterious figure. For instance, he could first appear to Harry in a dream, giving him cryptic messages. As the story progresses, we learn that he has his own motives, like seeking revenge on a wizard who wronged him in the past. His character could develop from being a bit of an enigma to a fully - fleshed - out ally with a complex backstory.
In fanfiction, goblins can help in various ways. For example, they might assist Harry Potter with getting access to certain Gringotts vaults that hold crucial items or information. Goblins are known for their skill in handling gold and guarding treasures, so they could use their knowledge to help Harry in his fight against Voldemort by providing him with financial resources or magical artifacts that were previously hidden away.
Some fanfictions create entirely new goblin characters. For example, there could be a young goblin prodigy who befriends Harry. This character could have extraordinary skills in metal - working magic, which is something goblins are known for in the Potterverse. They might use their skills to create powerful magical items for Harry or help him in his battles.
Maybe some of the Hogwarts professors like Professor Sprout. After all, she's the Herbology teacher. She could give Harry some expert advice on how to grow different kinds of food plants. She might even let him use some special greenhouses or tools in the school for his food - growing projects.
In Harry Potter fanfiction, goblin magic is often depicted as a unique and powerful form of magic. Goblins in the Potterverse are known for their skills in metalwork and their own brand of magic related to it. For example, they might use magic to create and enchant the famous Gringotts' vaults, which are highly secure. Their magic could also be related to their understanding of precious metals and gems, perhaps having spells to detect the purity or magical properties of such items.
In many Harry Potter fanfictions, goblins are often portrayed as highly intelligent and skilled beings. They are usually depicted as having a great knowledge of magic, especially when it comes to handling precious metals and objects like Gringotts' treasures. They are often shown to be proud of their heritage and magical abilities, and some fanfictions explore their relationship with wizards in more depth, sometimes highlighting the power dynamics and the goblins' sense of independence.
The Goblin King could interact with Hermione by challenging her intellect. For example, he might present her with a complex riddle related to goblin lore that she has to solve. With Ron, he could have an argument over food or some valuable item that Ron accidentally took from a goblin - owned place. And with Neville, the Goblin King might initially underestimate him but later be impressed by Neville's courage when they face a common threat together.
There could be an entirely new goblin character created just for this fanfiction. This goblin lawyer could be an outcast from the goblin community because of his more progressive views on wizard - goblin relations. Harry, seeing his potential, hires him to help with his legal battles that require a fresh perspective.
Yes, there are some fanfictions out there where the two universes cross paths and Harry Potter might help Superman in some way. You can try searching on popular fanfiction websites like FanFiction.net or Archive of Our Own.