Besides Padme, Anakin is a key character. Their love story is a big part of the Star Wars lore. Additionally, there could be characters from Padme's home planet who play important roles, like her family members or advisers. They might influence her decisions and actions throughout the novel. Also, some Jedi might be involved as they are often intertwined with the political and personal affairs in the Star Wars universe.
In some fanfiction set in a more peaceful time, they might interact with a lot of tender moments. They could have picnics and long walks, just enjoying each other's company and having deep conversations about their future.
Grover might also be involved. His ability to sense emotions and his connection to nature could play a role. He could be the one to initially sense Padme's arrival or help her understand the more magical and nature - related aspects of the Percy Jackson world, like the power of the gods and the spirits of the forest.
As Padme is pregnant, Anakin may start to think more about his future and his place in the galaxy. This could lead to deeper conversations between them about their values and what they want for their family. Their relationship will grow as they both adjust to the idea of becoming parents and all the responsibilities that come with it. They'll have to support each other through the physical and emotional changes that Padme is going through, and also deal with the external threats to their family.
Obi - Wan Kenobi would be one. He's Anakin's master, and in the fanfiction, he might suspect something about their relationship and have to decide whether to support them or uphold the Jedi Code.
Padme would most likely have an immediate emotional response. Tears might well up in her eyes as she sees Anakin burned. She would be in a state of disbelief at first, not wanting to accept that this has happened to him. But then, her natural instinct to care for him would kick in. She would use her influence to get the best medical care available, and she would stay by his side throughout his recovery, constantly reassuring him that he will be okay, even if she's not entirely sure herself.
The main distinction of porn with a story genre from regular porn is the presence of a coherent narrative. Regular porn often jumps straight to the sexual action, while the story genre tries to add some kind of story framework around it. But in the end, both are adult-oriented and feature explicit sexual content.