One idea could be exploring his childhood before Hogwarts and how wearing diapers was a normal part of that early life. Maybe there were some magical mishaps related to his diaper - like it magically changed colors based on his mood.
Another interesting plot could be a redemption arc for Peter Pettigrew. What if he had a change of heart during the events of the books and tried to make amends? Writers could show how the other characters react to his attempts at redemption, whether they believe him or not. It could also involve him using his skills in a positive way to help defeat Voldemort in the end. This would be a complex and engaging plot as it goes against the typical view of him as a traitor.
You can try websites like Fanfiction.net or Archive of Our Own. They have a large collection of fanfictions, and you can search for Peter Pettigrew fanfiction specifically. Just type in 'Peter Pettigrew' in the search bar and browse through the results.
Well, the theme of second chances is quite prevalent. Peter's time travel allows him to have a second chance at making different choices. This could be related to his loyalty to his friends or his actions in the wizarding wars. Additionally, the theme of time paradoxes is often explored. His actions in the past during time travel could have unforeseen consequences for the future, and fanfictions often play around with this concept. The exploration of the wizarding world's history is also a theme. As he travels through time, the reader gets to see different historical events and how they shaped the wizarding world.
If Peter Pettigrew was caught, it would likely have caused a major upheaval. The power balance in the wizarding world might have shifted, and the Order of the Phoenix could have had an advantage sooner. It's an interesting 'what if' scenario that could have taken the story in many unexpected directions.
Isolation is also a theme. Since Peter is often an outcast even among the bad guys, fanfics sometimes explore his loneliness. He's not really fully accepted by either side, and this can create some really poignant stories where he's just trying to find his place in a world that has shunned him.
First, do some research on Peter Pettigrew's character traits from the original Harry Potter series. This will help you write him in a way that is consistent with his known personality even when he is in diapers. For example, his sneaky nature could be shown in how he tries to get out of wearing diapers or how he hides things in his diaper.
One possible plot twist could be that Peter Pettigrew has a change of heart due to Hermione's influence. In the normal 'Harry Potter' universe, Peter is a cowardly and self - serving character. But in this lemon fanfiction, Hermione might be able to reach the part of him that still has some good in it. Maybe she discovers some long - lost magic within him that could be used for good. This would completely change the dynamic between them and lead to a series of events that are both unexpected and exciting.