I'm not sure specifically as I don't know the details of this particular story. But it could be a young child who is going through the normal process of being potty - trained and then something happens that makes them go 'back to diapers'. Maybe it's a parent or a caregiver in the story who has to deal with this situation.
In an 'back to diapers interactive story', the main characters could also include medical professionals if the story is set in a medical context. For example, if the 'going back to diapers' is due to a medical condition. They would play a role in diagnosing the problem and trying to help the patient deal with this unexpected and embarrassing situation.
Perhaps it's a humorous or satirical story. It could be about an adult who, out of laziness or just for fun, decides to go 'back to diapers'. The interactive part might allow the reader to choose different paths for the character. For instance, the reader could decide whether the character tries to hide this new 'lifestyle' from friends and family or is open about it, and how others react to it.
I really can't determine the main characters without more information. However, it could be a story about a patient in a hospital and the nurses or doctors involved. The patient might be put back in diapers for medical reasons, and the medical staff would play important roles in the story, either by helping the patient adjust or by being part of the situation that led to the need for diapers again.
It might be a story centered around two sisters. One sister could be more accepting of the diaper situation while the other is more rebellious, and their relationship dynamics could be a major part of the story.
Once upon a time, there was a girl named Lily. She was part of the ABDL community. One day, she decided to go back to wearing diapers as it made her feel a sense of comfort and security. She started her day by choosing a cute diaper with little stars on it. As she went about her day, she noticed how it affected her mood. She could be more carefree, not worrying about finding a bathroom all the time. She met some friends who also understood her choice, and they had a great time chatting and sharing their experiences, feeling accepted and happy in their own unique ways.
Since I don't know the specific 'going back to diapers story', I can't tell who the main character is. It could be an adult with a medical problem, a child who has a training regression, or just a fictional character created for the story.
Since we don't really know the story in detail, it could be the unruly boy himself as the main character. There might also be his parents or caregivers who play important roles in the story.
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 Griffins are at the center of it all. Peter, with his large gut and simple - mindedness, is always the source of much of the physical comedy. Lois tries to keep the family together. Meg is the underdog that the audience can often sympathize with. Chris is just trying to figure out life as a teenager. Stewie, with his teddy bear Rupert, is a character full of surprises. And Brian, who loves to write and drink martinis, is a unique addition to the family dynamic in the interactive story.
I'm not sure specifically as I don't know the details of this 'the company game interactive story'. But it could be the company's CEO, employees from different departments like the marketing manager, the IT guy, and the finance officer.
In 'ghoul school interactive story', the main characters could be diverse. There might be a new ghoul who has just transferred to the school. This ghoul would be trying to adapt to the strange environment. Then there could be an older, more experienced ghoul who acts as a mentor to the newbies. There may also be some antagonist ghouls who create problems for the other characters, like a bully ghoul who tries to steal other ghouls' magic items or a jealous ghoul who wants to be the best in everything.