Grover would be a bit more cautious. He might be a bit scared of the Norse monsters at first. But as he reads more, he'd start to see the similarities between the Norse and Greek worlds in terms of how nature is involved. He might notice how the Norse also have a connection to the natural world, like the wolves and the trees, and how it compares to his own connection to nature in the PJO universe.
Percy would probably find it hilarious. He has a good sense of humor and would likely enjoy the wild and crazy scenarios fans come up with. He might even share the funnier ones with his friends at Camp Half - Blood.
Some characters might be flattered. Like Percy, he could be happy to see that people are so interested in his story in 'The Son of Neptune' that they write fanfiction about it.
For demigods, it could either reinforce their existing views or introduce new perspectives. If a fanfiction delves deeper into a certain aspect of their world like the powers of a god, they might gain a new understanding. Mortals would have a more comprehensive view of the PJO world. They would learn about different characters and their backstories that might not be fully explored in the original books.
He would probably be quite amused by some of his past antics. For example, his constant pranks on Iruka-sensei. But at the same time, he'd also see the pain he carried from not having his parents and realize how that influenced his actions. He might react with a bit of regret for some of the stupid things he did out of loneliness, but also be glad that those experiences made him who he is today.
It can be considered common. There are a large number of PJO fans out there, and fanfiction is a popular medium in fan communities. Since the official books have a set storyline, fanfiction offers a chance to expand on it, so many 'mortals' (fans) are attracted to it.
One great 'athena pjo fanfic' is 'Athena's Wisdom'. It really delves into Athena's character in the Percy Jackson universe. The author does a wonderful job of showing her wisdom and how she interacts with the other characters. It has some really interesting plot twists that keep you hooked from start to finish.
I'm not entirely sure specifically as it could refer to different things, but generally a 'graphic novel' is a book in comic format. If 'pjo' stands for 'Percy Jackson and the Olympians', then it would be about the adventures of Percy Jackson in a graphic novel format. It might include his encounters with Greek gods, monsters, and his quests.
Well, one reason people read PJO fanfic is that they want more of the Percy Jackson world. The official books can't cover every single idea or relationship. Fanfiction fills those gaps. It might also be that some readers enjoy the different writing styles of fanfic authors. They can find unique interpretations of the characters and settings, which adds to the allure of the PJO universe.