What could be the plot of 'Harry Potter secretly trained' fanfiction?

One possibility is that Harry discovers a world where fanfiction has the power to change the real wizarding world. So he has to train to fight against the alterations caused by these fictional stories. For example, if a fanfiction made Hogwarts a place full of dangerous magical beasts that don't belong there, Harry would need to train to restore order.

Well, perhaps Harry could be trained in some long - lost or dark magic that Dumbledore has been hiding from him. This new training might make him even more powerful than before, able to defeat Voldemort in a more spectacular way.

Maybe Harry discovers some long - lost magic techniques taught by Godric. He could become super powerful and use ancient spells to fight Voldemort.

Well, in this fanfiction, it could be that Hephaestus trains Harry Potter to have a better understanding of the more physical and mechanical aspects of magic. For example, he might learn to build magical devices that can be used in battles or for other important tasks. This would give Harry an edge over his enemies as he'd have skills that no other wizard has. It could also lead to new alliances as other wizards might be interested in his newfound abilities.

Well, perhaps in this fanfiction, Harry discovers he has an affinity for snakes early on. Maybe he's able to communicate with them in a deeper way than Parseltongue allows. The snakes could train him in stealth and survival skills, like how to move quietly in the Forbidden Forest or find hidden passages. They could also teach him some unique magic that is related to the ancient magic of serpents.

Maybe it's about Harry learning some advanced magic spells from Flitwick. Flitwick could be teaching Harry unique charms or how to use his wand more effectively.

It could be that the SAS trains Harry Potter in modern warfare tactics. This would be a really interesting twist as he could combine magic with these new skills. He might learn how to use firearms in a Muggle - like way, but then enhance them with magic for more power and accuracy.

Well, perhaps Harry Potter could learn some unique magic skills from Zelretch. Maybe Zelretch teaches Harry how to manipulate time in a way different from normal wizarding magic. It could also involve Harry being trained in some super - advanced combat magic that gives him an edge against Voldemort and his Death Eaters.

The story could start with Harry finding an old family heirloom that has a connection to his ancestors. This item acts as a portal or a key to access the knowledge and training of his ancestors. They could train him in the art of wandless magic, which was more prevalent in the past. This would give Harry an advantage as he could use magic even when his wand is lost or broken. Also, his ancestors might teach him about the history of the wizarding world from a different perspective, helping him understand the roots of the dark magic that Voldemort uses and how to counter it.

In the 'Harry Potter Trained Killer' fanfiction, the plot could revolve around a time - traveling scenario. Harry Potter, having seen the future destruction of the wizarding world, decides to train a person from the past to be a killer. This person then has to go through a series of adventures and challenges. They have to learn combat skills from Harry, as well as how to be stealthy. Along the way, they discover secrets about the wizarding world that even Harry didn't know, and they have to use their new - found killer skills to protect these secrets from falling into the wrong hands.