Some forums dedicated to Rick Riordan's works might also have fanfiction shared by the community. You can search for ones that focus on 'The House of Hades' and look for the demigod - related stories there.
There could be a fanfiction where demigods from different cabins team up in the House of Hades in a way that wasn't shown before. They might have to solve puzzles and face challenges together, and their different abilities and personalities would create an interesting dynamic.
These fanfictions are popular because they give fans the chance to be creative with the story. Fans can take the existing world of the House of Hades and add their own ideas. The idea of gods and demigods reading about their own story in a way is also very meta and interesting. It attracts readers who want to see how the characters would react to their own story, and how they might change or influence the events in the fan - created scenarios.
One popular fanfiction could be 'Among the Gods in the House of Hades'. It has an interesting take on how the gods interact with the events of the House of Hades story. Another might be 'Demigods' View in the House of Hades Realm' which focuses on the perspective of the demigods as they experience the world within the House of Hades.
You can try some popular fanfiction websites like Archive of Our Own (AO3). It has a large collection of fanfictions including those for 'House of Hades'. Just search for 'House of Hades' in the search bar on the site.
The seven characters from the relevant series are probably the main ones in 'The Seven Read House of Hades Fanfiction'. They would be the focus as they navigate through the events and challenges in the House of Hades. It's possible that the fanfic author might also give more focus to certain characters among the seven, depending on the plot they are weaving.
I recall reading a fanfic called 'Hades' Hidden Treasures'. It was set in the House of Hades and explored some of the uncharted areas of the underworld. The author did a great job of creating a sense of mystery and danger, which made it really engaging. It also had some unique interpretations of the magic system within the House of Hades.
One thing that could happen is that they are either amused or offended by how they are portrayed. If the fanfiction writer has a very different view of their personalities, it could be quite a shock for them. For instance, if Leo is made out to be much more serious than he actually is in the books, the real Leo might find it really strange. Or if Piper is given some new powers in the fanfiction that don't exist in the original, they would have to figure out how that would work in the context of their world.
It would be quite an interesting scenario. The gods might be amused by the creative interpretations of their stories and characters in the fanfiction. Some might be offended if the portrayals don't match their self - perceived grandeur. For example, Zeus might not like being depicted as a bumbling fool in the fanfic.