One potential storyline could be Naruto having to re - experience his early life with his new - found child self's perspective. He might struggle with the lack of strength he once had as an adult. For example, he could have trouble with basic ninja training again, but this time with the knowledge of his future self, which could lead to some interesting twists. Another could be how his relationships change. His friends might initially not recognize him and he has to prove his identity in a rather comical way. And also, the villains might underestimate him as a child, which could be a great advantage for Naruto to outwit them.
Perhaps the cause of Kagome becoming a child in the fanfiction could be a cursed spell from a powerful demon. This demon might have wanted to weaken Kagome's powers as she was a threat. As a child, Kagome could have some child - like innocence and different abilities. For example, she might be able to communicate with certain spirits more easily because children are often seen as more pure in such fictional settings.
Mentally, his ninja skills could be both a help and a hindrance. On one hand, he has the knowledge of all the advanced techniques he learned as an adult. But on the other hand, his child - sized body might not be able to handle the chakra flow required for those techniques. His stealth skills might also change. As a child, he could potentially be more inconspicuous in some situations, but at the same time, he might lack the experience in using his smaller size to his advantage in a real combat situation.
In the fanfiction, Kagome's enemies could underestimate her. They think that because she's a child, she's not a threat. But in reality, even as a child, Kagome still has her strong will and some of her powers. She could surprise them by using her wits and the little bit of spiritual power she has left to outsmart them. For instance, she could lead them into a trap that her friends set up.
In the 'deku gets turned into a child fanfiction', it could lead to some really interesting storylines. Maybe he would see the world in a whole new way, with the innocence of a child. His interactions with his mentors could become more like a child - adult relationship where they have to guide him more. Also, his enemies might underestimate him at first, which could create some unique battle scenarios.
In a 'Seto gets turned into a child fanfiction', the plot might revolve around Seto's own struggle to adapt to his new form. He's used to being in control and powerful, but as a child, he has limited abilities. He could try to communicate with others about what happened to him, but with his child - like speech and behavior, it becomes a challenge. His friends might have to protect him from those who would take advantage of his vulnerable state.
In a fanfiction where Deadpool is turned into a child, his internal monologue would be hilarious. He'd probably still have all those wild thoughts running through his head, but they'd be filtered through a child's perspective. He might be more focused on things like getting ice cream or playing with toys, while also trying to figure out how to get back to his normal self. And his costume? It would probably be way too big for him, and he'd have to improvise, like using a belt to keep his pants from falling down, which would add to the comical effect.
In the 'deku gets turned into a child fanfiction', Deku is the main focus, but his friends like Uraraka and Iida would be key characters. Uraraka might be especially kind and motherly towards him. Iida could be strict in making sure Deku follows the right path. And villains like Shigaraki could see this as an opportunity to target Deku in a new way, so they would also be significant characters in this scenario.
The story could progress with Deadpool having to adapt to his new child form. He might start going to school in the fanfiction world. There, he could get into trouble for his unruly behavior that comes from his adult - like mindset in a child's body. Or he could make new friends who are actually kids and learn about the simple joys of childhood like building sandcastles or playing hopscotch.
The main antagonist could actually be Anakin's own self - doubt. Since he's in a child's body but has an adult's memories, he might struggle with feelings of inadequacy. This internal struggle could act as an antagonist, preventing him from fully embracing his new situation and using his abilities to the fullest. It could be a psychological battle within himself that holds him back more than any external foe.