Just from the title 'Adrienne messed her diaper', Adrienne is the main focus. But it's possible that in the fanfiction, there are other important characters in the background that influence the story. There could be a mentor - like figure who tries to teach Adrienne how to be more careful in the future. Or it could be that there are other children or adults in the same setting who are affected by Adrienne's situation in different ways.
Based solely on the title, Adrienne is clearly one of the main characters. However, we don't know if there are other characters involved. There could be a caregiver, like a parent or a friend, who helps Adrienne deal with the situation. Or perhaps there are antagonists who might make fun of her or add to her distress because of what happened.
There's not enough information given just from the title to know exactly what the fanfiction is about. It could be that the author is using this situation as a starting point for character development. Maybe Adrienne is a young character, and this event is used to show her growth or her relationship with other characters who help her through it. Or perhaps it's set in a world where such things are more common and has a different cultural or social context.
Her best friend could be a main character. They might be the one who discovers Adrienne's situation and either helps her or is the cause of it, depending on the plot. For example, if it's a medical situation, the friend could be the one who calls for help or stays by her side.
The 'Adrienne Filled Her Diaper' fanfiction could potentially be centered around a character Adrienne who experiences an embarrassing or unexpected situation of filling her diaper. It might be set in a particular fictional world, perhaps a world where she has some sort of disability or is in a very unusual situation. It could also be a way for the writer to explore themes of vulnerability or to create a unique and perhaps even a bit of a shock - value moment in the story. Without more context though, it's all speculation.
I'm not aware of any such Pokemon fanfiction. It's a rather unusual and unseemly topic for a fanfiction, and most Pokemon fanfiction tends to focus on more positive aspects like battles, friendships, and adventures in the Pokemon world.
Pikachu could be one of the main characters. Since Pikachu is so friendly and curious in the Pokemon world, it might be the first to approach Adrienne when she's in this new state. It could try to play with her or protect her from other Pokemon that might be a bit too rough. Another character could be Ash. Ash has a lot of experience with different Pokemon and strange situations. He might come across Adrienne and decide to help her. He could use his knowledge of Pokemon to find a way to get her back to normal or at least keep her safe while she's in this diaper - wearing state.
The implications would be quite negative. It could lead to a lot of criticism from the Pokemon fan base and the general public. The Pokemon brand is associated with values like friendship, courage, and exploration. Having a fanfiction with such an inappropriate topic would be at odds with these values. Moreover, it could discourage new fans from getting into the Pokemon world if they were to stumble upon such a disturbing piece of fan - made content.
Perhaps it's a fantasy - themed fanfiction. Adrienne could be in a magical world where she's been transformed into a younger state, and being placed in a diaper is part of the new reality she has to face. This could lead to adventures as she tries to find a way to reverse the transformation while dealing with the embarrassment and challenges of her new situation.
In the 'diaper days story', the main characters may include the infant who is in the diaper - wearing phase. This little one could be the focus, with their actions and reactions being central to the story. Additionally, if it's a more complex story, it could feature pediatricians or nurses who are involved in the baby's health during these diaper days. They could provide advice on diaper use, dealing with any potential health issues related to diaper - wearing, and so on.
Since I don't know the exact 'diaper boy story', it could be the boy himself as the main character. There might also be his parents or caregivers if the story focuses on his family situation.
Since I don't know the details of the story, I can't say for sure. But it might be the diaper - wearing boy himself as a main character. There could also be a camp counselor or a fellow camper who plays an important role.