A new generation of wizards and witches could be the main characters. For example, the children of Harry and his friends. They could inherit the legacies of their parents and at the same time, carve out their own identities as they struggle to survive and rebuild in a world that has been turned upside down.
Maybe Neville could be a central figure. He has always been strong and determined. In a post - apocalyptic world, his skills in Herbology could be extremely valuable. He could be in charge of finding or creating new plants that can provide food, medicine, or protection against the new threats in the world.
Luna Lovegood could be a main focus. Her unique perspective on magic could be used to discover new magical phenomena that emerged after the battle. She might also be helping the other students deal with their post - battle stress, using her calm and dreamy nature to soothe them.
One great post apocalyptic Harry Potter fanfiction is 'The Shattered World'. It presents a dark and desolate world after a magical cataclysm. The characters have to fight for survival in a way that's very different from the original series. Another one is 'Surviving the Ruins' which focuses on how the Hogwarts students band together against new and terrifying threats.
It could be a young, inexperienced trainer. They were just starting their journey when the apocalypse hit. This character would be learning about the new, post - apocalyptic world of Pokemon while also growing as a person. Their inexperience could lead to some interesting situations as they make mistakes and learn from them.
Perhaps a group of radical wizards who believe that the apocalypse was a sign that the old ways of the wizarding world were wrong. They want to create a new order, even if it means using cruel and unethical magic. They see the more traditional wizards, like those who were friends with Harry Potter, as enemies who are holding back progress.
Survivors like a former fisherman who knows the waterways well could be a main character. He can help others navigate through the flooded parts of the city.
In post apocalyptic Harry Potter fanfiction, a common theme is the breakdown of the old order. Hogwarts might no longer be the safe haven it once was, and the Ministry of Magic could be in ruins. This forces the characters to create new systems and ways of living. Another theme is the discovery of new powers or abilities. With the world in chaos, some characters may find hidden strengths within themselves that they never knew existed before, which helps them in their fight for survival.
Neville Longbottom could be a main character. He has always had the potential for great things and in a world without Harry, he would be likely to step into the spotlight. He has the courage and the connection to Hogwarts that could make him a central figure in the fight against evil.
I'm not sure specifically as I haven't read this novel. But typically in a post - apocalyptic novel, there would be a strong - willed protagonist, perhaps a survivor who has some special skills like hunting or fixing things. There might also be a sidekick character, someone who provides support or a different perspective to the protagonist. And there could be an antagonist, like a group leader who is power - hungry and causes trouble for the good guys.
One interesting concept could be the rebuilding of Hogwarts. After an apocalyptic event, the once - great school might be in ruins. The remaining wizards and witches could come together to restore it, using their magic in creative ways. They might have to find new sources of magical energy or deal with dark magic that has been unleashed during the apocalypse.