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.
The plot might involve the goblins approaching Harry Potter for help in protecting their underground kingdoms from a new threat, like a horde of dark creatures. Harry, being the hero he is, agrees to form an alliance. They then train together, combining wizard magic with goblin technology and combat skills. This alliance not only helps in fending off the threat but also makes the wizarding community re - evaluate their relationship with the goblins.
One main character could be Griphook. He already has a complex relationship with Harry Potter in the original series. In a goblin rebellion fanfiction, he could be a key figure leading the goblin revolt, using his knowledge of the wizarding world and his own skills to strategize against the wizards. Another character could be a young goblin apprentice who is caught between his loyalty to his own kind and his admiration for Harry Potter and the wizarding world.
It's hard to say without reading it, but it could be Harry Potter himself. Since it's set in the Harry Potter universe, he might be involved in the goblin - related surprise. Maybe Hermione and Ron could also be part of it, as they are usually by Harry's side in most adventures.
Harry Potter is the obvious main character. The goblin would be another main character. In addition, there could be a wizard or witch who is either helping or hindering Harry and the goblin in their adventures involving the lemon. Maybe it's a teacher from Hogwarts who has some knowledge about the goblin - lemon connection.
Obviously, the Goblin Prince would be one of the main characters. Harry Potter would also be a central figure. There might also be other characters like Hermione and Ron who could get involved in the story, perhaps as they try to understand the motives and actions of the Goblin Prince. And of course, there could be various goblin characters who are part of the Goblin Prince's court or family.
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.
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.
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.
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.
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.