Well, Harry Potter might be really confused at first. Lovecraft's works are full of cosmic horror and a very different kind of magic compared to the magic in the wizarding world of Harry Potter. He would probably be shocked by the dark and often nihilistic themes in Lovecraft's fanfiction.
The plot could change drastically. Harry might become more paranoid about the unknown threats in his world. He could start seeing potential Lovecraftian - like entities in the Forbidden Forest or in the shadows of Hogwarts. This new - found fear could make him more hesitant in his adventures and less likely to jump into dangerous situations without more information.
One common theme is the clash between the known magic in Harry Potter and the unknown, cosmic horror of Lovecraft. It's like seeing how the structured magic of Hogwarts stands against the chaos of Lovecraftian entities.
Well, it could be really strange for him. He might find some of the interpretations of his life and adventures quite off - putting or amusing. Maybe he'd be shocked to see how some fans have romanticized his relationships in ways he never thought of.
A popular Litrpg Harry Potter fanfiction is 'Gryffindor's Ascension'. In this story, the characters are more aware of their skills in a Litrpg sense. For example, they can see their magic power levels. It's a really interesting concept that adds a new layer of depth to the Harry Potter universe. There's also 'Slytherin's Redemption' which has a great plot that incorporates Litrpg features like quests and rewards within the Hogwarts setting.
I really like 'Ghostly Encounters in Hogwarts'. This fanfiction delves into the idea of Harry being able to see and interact with ghosts in a way that no one else can. It shows his unique connection to the spirit world within Hogwarts, and the adventures that come with it are quite exciting. It also has some great character development for Harry as he learns more about the ghosts and their stories.
There's a fanfiction called 'Cedric's Unfinished Story'. In this one, it explores what could have happened if Cedric had survived the Triwizard Tournament. It's really interesting as it weaves new adventures for Cedric, involving him in the fight against Voldemort in a different way.
Yes, it's completely normal. Harry Potter has a huge and detailed world, and fanfiction allows fans to explore parts of it that the original books might not have covered fully. It gives people a chance to imagine different scenarios for their favorite characters, like what if Harry had been sorted into Slytherin? So it's natural for your friend to be into it.
There's a fanfiction titled 'Harry Potter: Albus's Destiny'. It focuses on how Albus Severus Potter discovers his own unique path in the wizarding world, different from his father's. It's a great read as it shows his struggles and how he overcomes them.