Another theme could be identity. With this new title of sergeant, Harry has to re - evaluate who he is. It could be about how he balances his magical identity with this new, more militaristic identity. It might also deal with how others in the wizarding world view him now.
A possible theme is adaptation. Harry has to adapt to the expectations that come with being called sergeant. This could involve new rules, new relationships, and new challenges. It might show his journey of learning and growing in this new role within the context of the fanfic's unique world - building.
One common theme could be leadership. Since he's called sergeant, it might explore Harry's leadership skills in a different way than in the original books. Maybe he's leading a group in a non - magical or alternate - universe military - like situation.
I'm not sure of specific 'harry is called sergeant potter fanfic' stories off - hand. You could try searching on popular fanfiction websites like Archive of Our Own. They have a vast collection of Harry Potter fanfics, and you might be able to find ones with this interesting concept.
One common theme is the exploration of an alternative relationship. Instead of the more well - known pairings in the original series, it focuses on Harry and Daphne. Another theme is often the discovery of new magical elements. Since they are two different characters with different backgrounds, they might uncover something new together. Also, the theme of self - growth is present. As they interact, both Harry and Daphne usually grow as individuals.
A third theme is the element of disguise and secrecy. Crossdressing can be used as a form of disguise, much like the invisibility cloak in the original story. Fanfics often explore how Harry uses this new form of 'disguise' to his advantage, whether it's to outwit enemies or to gain access to places he otherwise couldn't.
Friendship and acceptance is also a big theme. The merman character is usually an outsider in the Hogwarts world, and the story often focuses on how the other characters come to accept and befriend him. This is similar to how Harry Potter was an outsider at first in the wizarding world but found his place. In some fanfics, the merman might face discrimination at first because of his different appearance and abilities, but then through his actions and the kindness of others, he becomes part of the community.
One common theme is the clash between the traditional wizarding legal system and new ideas. For example, a fic might explore how a young wizard or witch, trained in modern legal thinking, tries to reform the archaic laws of the Ministry of Magic. Another theme could be justice for the underrepresented, like house - elves or half - bloods. In these fics, the lawyer character would fight for their rights. Also, there's often the theme of mystery and intrigue as the legal cases might involve dark magic or secret societies within the wizarding world.
One common theme is the exploration of different social hierarchies. In the omegaverse, there are alphas, omegas, and betas. Fanfics often show how these hierarchies play out within the Hogwarts environment. For example, an alpha might be a natural leader in a Quidditch team.
Friendship is a big one. The Marauders were known for their tight - knit group, so fanfics often explore their deep friendships. Another theme is loyalty. They were loyal to each other through thick and thin.
One common theme is sacrifice. Mothers in the Harry Potter world, like Lily Potter, often sacrifice themselves for their children. In fanfics, this is explored further, showing how their sacrifice has far - reaching consequences. Another theme is protection. Mothers are always trying to protect their kids from the dark forces in the wizarding world.
One common theme is the struggle against prejudice. Werewolves in the Harry Potter universe are often discriminated against, and fanfics usually explore how they deal with that. For example, they might fight for equal rights within Hogwarts or the wizarding world at large.
One common theme is the fight for freedom. Just like in the original series, the resistance in these fanfics is often about breaking free from oppressive forces.