In a Harry Potter final battle fanfiction, Harry might use some new and unexpected spells. For example, he could combine the Patronus Charm with a powerful offensive spell to repel the Death Eaters in a more spectacular way. Maybe he discovers a hidden power within himself that gives him an edge in the fight.
In many fanfictions, after the final battle, Harry might focus on rebuilding Hogwarts. He could use his influence to make it a more inclusive and modern place of magic learning, with new courses perhaps on Muggle technology and its integration with magic.
Obviously, Harry Potter is one of the most important. His role as the Chosen One is central to the final battle. Hermione Granger also plays a crucial part with her intelligence and knowledge of magic. Ron Weasley too, as he provides support to Harry.
The house - elves could be unsung heroes. In fanfiction, they might use their magic in ways that the wizards and witches don't expect. Since they are so good at household magic, they could turn that to their advantage in the battle. For instance, they could make the Hogwarts castle even more of a maze for the Death Eaters to navigate, or they could use their skills to quickly repair any damage done to the castle's defenses.
It could be Luna Lovegood. She has a unique perspective on magic. In the final battle fanfiction, she might use her strange but effective magical items and her unorthodox thinking to outwit Voldemort. For example, she could use some of her Lovegood family's special magical artifacts to create a shield or a trap for the Dark Lord.
Obviously, Harry Potter himself would still be a central character. He would be dealing with the aftermath of the battle, like post - traumatic stress or trying to bring about positive changes in the wizarding world.
One possible plot twist could be that Neville discovers a new and powerful spell that turns the tide of the battle. Another could be that Draco Malfoy has a change of heart and secretly helps the Order of the Phoenix during the final battle.
One interesting plot twist could be that Neville Longbottom discovers a new, powerful spell that can turn Voldemort's own dark magic against him during the final battle. This would change the dynamic of the fight as it gives the good side an unexpected advantage.
The relationship between the different houses might improve significantly. With the end of Voldemort's reign of terror, the old rivalries between Gryffindor, Slytherin, Hufflepuff and Ravenclaw would start to fade. Students from all houses would work together on projects, share study spaces, and even form inter - house Quidditch teams. There might be more unity among the wizarding community as a whole.
Well, one possibility is that Harry, Ron and Hermione would focus on rebuilding Hogwarts. They might use their magic to restore all the damaged parts of the castle, making it even more magnificent than before. And they could start new magical education programs to ensure that future wizards and witches are well - trained in both magic and ethics.