One reason could be for comedic effect. Diapers can be used in a humorous way, like when a character is put in an embarrassing situation related to diapers, perhaps a clumsy character accidentally wearing one or getting diaper - related tasks wrong.
It could also be part of a story about child - rearing or taking care of infants. If the anime is centered around family life or childcare, then a diaper story might be a natural part of showing the daily tasks and challenges involved. For example, an anime about a single father raising a baby would likely include diaper - changing scenes as part of the realistic portrayal of parenting.
Sometimes, in anime with a more surreal or absurdist style, a diaper story might be used to create a sense of the unexpected or to break the normal flow of the narrative. It can be a way to shock the audience or make them think in a different way by introducing such an out - of - the - ordinary element.
In some cases, it could be a part of a unique world - building concept. If the anime is set in a world where magic or some strange phenomenon can turn people into different forms, a girl turning into a baby - like form with a diaper could be just one aspect of that strange and interesting world. It can add a touch of quirkiness to the overall setting of the anime.
Medical issues like incontinence are a possible reason. Some students may have a condition that affects their ability to control their bladder or bowels.
It might also be used in a comical context. Sometimes, authors use unexpected or embarrassing situations like an adult wearing a diaper for comedic effect. It can play on the contrast between what is considered normal for adults and this out - of - the - ordinary situation. However, this has to be done very carefully to avoid being offensive. Also, in some cases, it could be part of a character's backstory to show vulnerability or a difficult situation they are in, like in a story about an elderly person with health issues.
One possible reason could be for a medical condition. Maybe the boy has a physical disability or a medical issue that requires him to be in a diaper for a long time and some situation led to him being locked in a room while in that state. Another reason could be a form of punishment in a very cruel and inappropriate scenario which is of course not acceptable in normal circumstances.
One reason could be that she was too busy playing and ignored the urge to go. For example, if she was building a big tower with her blocks and was so focused on making it taller that she didn't pay attention to her body's signals.
One reason could be a medical condition like incontinence. Some students might have a physical problem that makes it necessary to wear a diaper to avoid accidents. Another reason could be a psychological factor. For example, in very rare cases, extreme anxiety might lead a student to have a fear of not being able to reach the bathroom in time, so they choose to wear a diaper as a precaution. However, this is not a common or healthy long - term solution.
It could be due to negligence or abuse. In a story, if she is in the care of someone who is cruel or neglectful, they might force her to use a diaper instead of providing proper toilet training or access. This could be used to highlight the power imbalance and the unjust situation she is in. Also, in a post - apocalyptic story, resources might be so scarce that diapers are the only option available for some reason, and she is forced to use them against her will.
One reason could be that the kid has some special needs or medical conditions. For example, if the kid has problems with bladder control due to a physical disorder. Another possibility is that there was a misunderstanding or an emergency situation at home where the parents didn't have time to change the kid out of the diaper properly before sending them to school.
One possible reason could be a medical issue like incontinence. It might be due to a physical problem that the boy has no control over his bladder or bowel movements. Another reason could be in a very extreme bullying situation where something cruel was done to him, though this is a very dark and unlikely scenario in a normal school.
Low ratings. If not enough people were watching, the network or studio might not have wanted to keep investing in it to finish the story. It's all about the money in the end. If it's not making a profit, they'll cut it short.