It could be a young witch or wizard who is a transfer student to Hogwarts. They would be the main character as they try to adapt to the new environment and in the process, discover a magical mystery that sets them on a journey.
It could be about a new student at Hogwarts who discovers a hidden magical ability and embarks on a journey to uncover its origin. This journey might lead them to encounter forgotten spells, mysterious creatures, and make new friends along the way.
Perhaps it could be an older version of one of the main characters from the original series. For instance, an adult Harry Potter who has become a master of certain types of magic and is now on a new adventure. He could be traveling to different parts of the wizarding world to teach or to learn more advanced magic techniques. Another possibility is that it could be a character like Dumbledore in his younger days when he was on his own journey to become the great wizard he was known to be.
Another possibility is that it's a descendant of an ancient wizarding family. This character has been sheltered from the wizarding world until they discover their second magical core. Their family's secrets and history could be intertwined with the nature of this second core, and they have to navigate the wizarding world while also uncovering their family's past.
Neville would also make an excellent main character. He has a natural affinity for plants, and magical creatures are not that far off in the wizarding world. He could be the one to discover a new way to care for ailing magical creatures, perhaps using his knowledge of herbology. For example, he might find a plant that can cure a disease that's been affecting the unicorns in the forest.
It could be a new character, like an assassin from a far - off land who comes to Hogwarts under false pretenses. They have their own set of skills and motives that are different from the regular characters in the Harry Potter series.
It could be a young witch who is just starting to explore her magical abilities outside of Hogwarts. She takes on a babysitting job to earn some extra money and ends up having all sorts of magical adventures with the kids she babysits.
A Muggle - born wizard could be the main character. They are used to the Muggle concept of hairdressing but also want to incorporate their new - found magic into it. This character would be constantly trying to bridge the gap between the two worlds in their salon, creating a unique blend of Muggle and wizarding hairdressing styles.
Obviously, Harry Potter himself could be the main character. Given his adventurous nature, he would be a great fit to incorporate parkour into his already impressive list of skills. He could use parkour to explore new areas of Hogwarts or to escape from dangerous situations.
Perhaps Accelerator from the railgun universe could be the main character. He has his own set of abilities that would be very interesting to transplant into the Harry Potter world. He might initially be seen as a threat due to his powers but then end up using them to fight against a common enemy, like a new dark wizard or a powerful magical creature that has gone rogue.
It might also be a descendant of one of the well - known characters from the Harry Potter series. For example, a grandchild of Sirius Black who inherits his rebellious spirit and uses it to fight against the new dark forces as the 'darkslayer'.