In such a fanfiction, Harry might discover ancient spells that give him an edge in battles. For example, he could learn old defensive magic that can protect Hogwarts in a more powerful way than the existing spells. He might also use old magic to communicate with long - lost magical creatures that hold secrets of the wizarding world.
One possibility is that Harry learns old magic that has a deep connection to the founders of Hogwarts. This old magic could help him understand the true purpose of the school and its hidden chambers better. It could also lead him to find new magical artifacts that were lost for centuries, which could in turn change the balance of power in the wizarding world.
Maybe it could be an ancient magical being like a centaur. Centaurs are known for their knowledge of the stars and ancient magic. They might take Harry under their wing and teach him old magic that has been passed down through their generations.
In 'Harry Potter Learns Voodoo' fanfiction, perhaps Harry would learn voodoo from a mysterious character who has some connection to the wizarding world. He could then combine voodoo spells with his own Hogwarts - taught magic. For example, using a voodoo charm to enhance his invisibility cloak's power. This would open up a whole new set of adventures and challenges for him as he tries to master this new form of magic while still dealing with the regular threats in the wizarding world.
It could be an older relative who was thought to be dead but actually has been living in seclusion, waiting for the right time to teach Harry about their family magic. This relative might have a vast knowledge of the family's magical traditions and spells.
Naruto could use his newfound magic to make alliances with other magical beings. This would expand his influence and power base. He could then use these alliances to either seek revenge on those who wronged him or to protect the world from greater threats that the ninja world alone couldn't handle. In this fanfiction, the possibilities are endless as magic adds a whole new dimension to his character.
Well, if Harry Potter learned Fairy Tail magic, he'd probably become even more powerful. He could combine spells like Expelliarmus with Fairy Tail's powerful attack magic. His adventures would take a whole new turn as he'd have different ways to fight the dark forces.
Well, he might be really confused at first. Fanfiction often takes the original story in different and sometimes wild directions. He could be shocked to see how some fans have imagined his relationships or new adventures that are quite different from his own experiences.
Perhaps it's a magical crystal that enhances his ability to communicate with magical creatures. This would be quite unique as it would give him an edge in dealing with things like thestrals or unicorns, and open up new storylines in the fanfiction. Harry could use this crystal to understand their needs and gain their help in various situations.
The Death Eaters could still be the main antagonists. If Harry starts learning soul magic, they might see it as a threat and try to stop him.
Well, it could be that the magic book is sentient and starts to communicate with Harry. It could offer him advice on how to defeat Voldemort in a completely new way, like revealing a long - forgotten prophecy.
In this fanfiction, Harry could become a sort of living magic conduit. He could be able to manipulate magic in ways that are unheard of. He might be able to merge different spells together to create entirely new and powerful incantations. And perhaps he could use his new oneness with magic to heal the most serious of magical ailments with just a touch.