One great fanfiction could be 'The Hidden Path in the House of Hades'. It explores the relationship between Percy and Annabeth in more depth during their time in the House of Hades. The author adds some really interesting side quests that the characters embark on, which makes it a thrilling read.
One common theme is self - discovery. As Percy reads the story, he often reflects on his own journey and discovers new things about himself. Another theme is the exploration of the relationships between the characters. Fanfics might focus on how Percy's view of his friends and enemies changes as he reads through The House of Hades.
There's also a fanfic called 'Percy and the Mysterious Reading of The House of Hades'. In this one, Percy's reading of the book is not just a simple read. Strange things start to happen around him as if the events in the book are coming to life in a way. It's really exciting and full of mystery.
Percy and Annabeth are often very popular. Their relationship is a central part of the series, and in fanfiction, people like to explore different aspects of it, especially during their trials in the House of Hades.
The 'Redemption Arc' is also common. Some fanfictions focus on a character who has made mistakes in the past, like a minor villain, and they get a chance to redeem themselves in the House of Hades setting. It adds an interesting layer of depth to the story.
Maybe he faced an extremely powerful enemy that he couldn't overcome. It could be a new and terrifying monster created by the Titans or some other dark force.
He might be interested in exploring the different ideas that fans have. Fanfiction can take the basic elements of the House of Hades and turn them into something completely new. For example, there could be fanfictions that change the setting or the outcome of certain events. Percy could be curious about these alternate versions of his world. Also, he may enjoy reading about himself in different situations that the original author didn't explore, like teaming up with unexpected characters or facing different challenges.
Percy and Annabeth are always interesting. Their relationship is central to the series, and in the House of Hades, they face extreme challenges that can be explored further. Their love and loyalty to each other can be put to the test in different ways. For example, when they are separated, how do they each cope and still strive towards their common goal? Another interesting character is Nico. He has a deep connection to the underworld and his own complex backstory. In the House of Hades, his powers and knowledge could be further developed in fanfiction.
You could write a fanfiction where the House of Hades has a sort of time - warp effect. The demigods find themselves reliving parts of their past traumas while in there. This would not only be a great way to explore their backstories more but also add an element of psychological horror. Also, what if there was a character from Greek mythology that they thought was long dead but is actually alive and trapped in the House of Hades? They could then try to rescue this character while also fulfilling their main mission.
A fanfiction could be about the other characters' reactions when Percy and Annabeth are in the House of Hades. For example, how Nico feels knowing they are in such a dangerous place and what he does to try and help them from the outside.