It could be Dumbledore. He always has a knack for providing Harry with useful tools. Maybe he found this device during one of his travels and thought it would be beneficial for Harry's growth as a wizard.
Maybe Harry Potter uses a magical device to learn advanced spells. For example, he discovers a time - turning quill that allows him to study ancient magic more efficiently.
If the device in the fanfiction is a time - traveling gadget, it could completely transform Harry's life. He could go back in time to learn from the founders of Hogwarts, understand the origin of certain dark magic, and use this knowledge to prevent future disasters in his own time. It would also give him a chance to meet his parents and gain a deeper understanding of his own heritage.
It could be a magical time - traveling device. Maybe it allows Harry to go back in time to change certain events in the wizarding world, like preventing some of Voldemort's early atrocities.
In this type of fanfiction, the relationship between Harry and Snape can be re - imagined. Snape was Harry's teacher for Occlumency in the books, but often their interactions were tense. Fanfic writers may change this dynamic. They could have Snape be more patient or Harry be more receptive, which would lead to a different kind of mentorship and a new understanding between them.
One interesting lesson could be table manners in the wizarding world. There might be specific ways to hold a wand while dining or proper incantations to say before and after a meal. Another could be how to address different levels of wizards and witches, like the proper title for a powerful elder wizard. And perhaps the correct way to enter and exit a magical room or building, which could involve specific spells or gestures.
Maybe a wizard who has traveled to far - off lands where voodoo is practiced could teach Harry. This wizard could have seen the power of voodoo and thought it could be useful in the fight against the Dark Arts in the wizarding world of Harry Potter.
In fanfiction, a device could teach Harry Potter about advanced magic theories. Imagine a device that contains the collective knowledge of all the great wizards in history. It could show him spells that have been long forgotten or new ways to manipulate magic. This new knowledge could help him in his battles against Voldemort and also in his journey to become a more powerful and well - rounded wizard.
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.
Another reason is that it allows for a lot of creativity. Writers can create new mentors for Harry to learn from, new techniques of Legilimency, and new consequences of using it. It's a topic that can be combined with other elements of the Harry Potter world, like the prophecy, the Horcruxes, and the wizarding politics, creating a rich and engaging fanfiction.