Definitely the two male leads. Their competitive and comical relationship is the heart of the movie and can be explored further in fanfic. You can show more of their backstory and how they became such rivals.
A fanfic could center around the idea that the girl they were fighting over in the movie actually has a secret identity as a spy. When they find out, they have to team up with her to take on a bigger threat, all while still dealing with their feelings for her.
One popular 'this means war hp fanfic' might be the one where the characters are put in a unique magical battle situation that mimics the 'this means war' concept. You can try looking on fanfic platforms like Archive of Our Own. They usually have a good collection of such stories.
The main characters could include some of the new generation as well. For example, Albus Potter or Scorpius Malfoy. They could be at the center of this 'war' in the fanfic, perhaps dealing with the consequences of their parents' actions. Ginny Weasley could also be a main character, as she's a strong witch in her own right. And then there are the Hogwarts professors. Professor McGonagall could be leading the defense of Hogwarts in this war - like situation, and Professor Flitwick could be using his magical expertise to help the side he's on.
Well, a typical plot element might be the discovery of a new, powerful magic item or spell. In this 'This Means War' fanfic, different characters or groups could be fighting over it. It could be that the item has the potential to change the balance of power in the wizarding world. Additionally, betrayal is often a great plot element. A character who was thought to be on one side might switch, creating chaos and fueling the 'war'. And of course, love interests can also play a role. Two characters from opposing sides might fall in love, adding an extra layer of complexity to the conflict.
The Return of the God of War was a term commonly used in novels to describe a hero or God of War who returned to his hometown or battlefield to start a fierce battle again after experiencing a series of battles and adventures. This phrase was often used to describe a character who had become stronger and more determined after a long period of departure and return.
One common theme is friendship. Tuck often forms new friendships or strengthens existing ones in these fanfictions. Another theme is adventure, as Tuck is usually involved in some sort of exciting journey.
Terrified means to describe extreme panic and fear, causing people to feel extremely shocked and terrified. Calmness meant that one's thoughts or spirit were calm without uneasiness or suppressed feelings. One had suppressed or re-restrained one's feelings and calmed down.
Well, one interesting aspect could be the unique character interactions. In a 'This means war' type of scenario within the Harry Potter universe, we might see characters who are usually allies having to compete or oppose each other in new ways. For example, Gryffindors and Hufflepuffs could be on opposing sides for some reason, leading to interesting dynamics between friends from different houses. Another aspect could be the creative use of magic. The author might come up with new spells or ways of using magic in the context of this 'war' situation, which adds a fresh perspective to the already rich magical world of Harry Potter.