Since it's a 'pjo fanfic' with 'the dark gamer' in it, it could be about a gamer who has a rather dark or edgy personality. In the context of the Percy Jackson universe, this gamer might enter the world through some sort of magic or accident. Once there, they could start to change the dynamics of the story. For example, they might use their gaming knowledge in unexpected ways to battle monsters or solve puzzles. They could also form alliances with some of the more unconventional characters in the PJO world, all while their 'dark' side adds an interesting twist to the plot.
A big theme is also about power and responsibility. As a mercenary, Percy has power in his skills and abilities, but he also has the responsibility to use them for good. In many fanfictions, he struggles with how far he can go in his mercenary work without compromising his values. For example, he might be offered a large sum of money to do something that goes against his moral code, and how he deals with that is a central part of the story. This theme is explored in different ways in different fanfictions, sometimes more subtly and sometimes more directly.
The theme of powerlessness is quite common in 'percy begs pjo fanfic'. Percy, who usually has some level of control in the main series, is now in a position where he has to beg. This shows that there are forces or situations that are beyond his normal ability to handle. And there's also the theme of hope, as his begging could be a last - ditch effort to find a solution to a seemingly impossible situation.
One common theme is adventure. Percy is always going on some sort of journey or quest. Another is friendship, as he relies on his friends like Annabeth and Grover. And of course, there's the theme of power, especially related to Percy's unique abilities which might be emphasized more in fanfics about his tail.
Yes, there are several. Some focus on exploring how Percy's life would be different if he was born a monster. For example, in some fanfics, his relationships with other characters are completely reimagined. He might face more prejudice or have to find new ways to fit in the world of demigods and monsters.
I don't really know for sure as I haven't read it. But it could be the 'dark gamer' themselves as the main character. There might also be some of the original PJO characters like Percy Jackson or Annabeth Chase who interact with this new 'dark gamer' character.
If Percy is exiled in this PJO Avengers fanfiction, it could lead to some really interesting story developments. Since he's used to having his friends and allies around in the Percy Jackson series, being alone in the Avengers' world would be a big change. He might start to discover new powers or abilities as he struggles to survive. And there could be a whole plot about him trying to prove his worth to the Avengers so he can be accepted back.
It could be a group of fans who collaborate on the story. They might each contribute different parts or ideas. For example, one person could be good at writing action scenes, another at character development, and they come together to create this 'Percy has a tail' fanfiction.
One possible plot could be Percy trying to find a way back home. He might have to complete certain quests or tasks set by the Avengers or some other powerful entity in the fanfiction world. Another plot could be Percy getting involved in a conflict that he wasn't originally a part of because of his exile, like a battle between different superhero factions.
The relationship can also be shown as very loving. Poseidon might secretly watch over Percy and be proud of his son's achievements. He could send signs of his support during Percy's battles or quests. And Percy, in turn, is always eager to make his father proud and show that he is a worthy son of Poseidon.