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.
The plot could involve a situation where Harry Potter hires a goblin lawyer to fight against the unfair treatment of house - elves in the wizarding world. He might want to use legal means to change the laws regarding their servitude. Since goblins have their own ideas about fairness and legality, the goblin lawyer could be crucial in formulating a legal strategy for this noble cause.
It could be Hermione. She's always been very book - smart and she could have decided to study law in the wizarding world. She already has a great understanding of the rules and regulations at Hogwarts, so it would be a natural progression for her to become a lawyer. And she would be very dedicated to helping Harry with any legal issues.
One possibility could be that Harry Potter hires a lawyer to deal with the legal mess left behind by the wizarding wars. For example, he might need help in getting proper compensation for the damages done to the wizarding community. The lawyer could be a Muggle - born wizard who has knowledge of both worlds' legal systems and uses that to fight for the rights of those affected.
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.
Hermione Granger could be a great candidate. She is extremely intelligent, has a deep understanding of the wizarding laws (from all her studies), and is very determined. She could use her knowledge to fight for justice as a private lawyer. Her Muggle - born background might also give her an edge in dealing with situations that require a different perspective from the traditional wizarding view.
Luna Lovegood might be an unexpected but interesting choice. She has a unique perspective on the wizarding world. While she may seem a bit eccentric, her ability to think outside the box could be useful in a courtroom. She could come up with creative defenses for Harry, and her calm and dreamy nature might be able to sway a jury or judge in Harry's favor.
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.
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.
Obviously, Harry Potter would be one of the main characters. And Griphook, the goblin we know from the books, could also be a main character as he has prior interactions with Harry. Another could be a young, rebellious goblin who wants to change the relationship between goblins and wizards and is the driving force behind the alliance.
It could be a new student at Hogwarts. A young wizard or witch who has always been curious about goblin magic. Maybe they come from a family with a long - standing interest in different magical cultures, so they jump at the chance to train with goblins.