One main theme could be sacrifice. Just as in the original series, characters might make sacrifices at the end of all things to save their world. Another could be redemption, where characters who have made mistakes find a way to make up for them in the end.
Well, it could potentially be about the final events or conclusion in a Harry Potter fan - made story. Maybe it focuses on how the characters' arcs end, like Harry, Hermione and Ron. It might also explore the end of the magical world as imagined by the fanfic author, with things like the fate of Hogwarts and the wizarding society.
Well, he might bake some butterbeer - flavored cookies. Since butterbeer is a popular drink in the Harry Potter world, it would be a great idea to turn it into a baked good. Also, he could bake owl - shaped pastries to feed his owl, Hedwig.
The themes could include respect, of course. Harry showing respect for the goblins might lead to a broader exploration of how different magical beings should respect each other's existence and rights. Also, there could be a theme of redemption, perhaps if the fanfiction involves Harry trying to make up for past wrongs that wizards have done to goblins. And cooperation might be another theme, as Harry could be working with the goblins towards a common goal.
Power would be a major theme. Since Harry is the 'black king', it implies a great deal of power and perhaps a different kind of leadership. Another theme could be identity, as Harry has this new role that is quite different from his traditional one.
Prejudice and its overthrow. The fanfiction could explore how deep - seated the prejudice against Muggle - borns is in the wizarding world and how the revolution aims to uproot it. Also, the theme of unity. Muggle - borns from different backgrounds would need to come together to be successful in their revolution. They might have to overcome differences in their Muggle cultures and find common ground in their magical abilities.
Hermione would probably still be an important character. Since she's Harry's friend, she might try to convince him to stay involved in the wizarding world's affairs, or she could support his decision to take a break.
Well, it could lead to a lot of chaos. Characters who were once working together might start working against each other. For example, if the wizarding schools' alliance ends, there could be rivalries and even duels between students. It could also mean that some characters have to find new allies, like Hermione might have to seek help from other magical creatures instead of relying on the previous alliance members.
One reason could be that the author deviated too much from the original lore of Harry Potter. Fans are used to certain characters' personalities, magical rules, and the overall world - building. If a fanfiction changes these elements in a way that doesn't seem right, it can create a sense of 'all was not well'. For example, if Hermione was suddenly written as a very ditzy character instead of the intelligent and studious one we know.
Maybe Harry is tired of the constant danger and battles. He might decide to take a break from the wizarding world, perhaps go into hiding in a Muggle village to find some peace.
It might be a new, extremely powerful villain that combines the powers of all the previous villains Naruto has faced. This character could be seeking to destroy the ninja world for some grand, twisted reason.