Naruto's sickness could be a major turning point in the story. It could change his perspective on his powers and his role in the ninja world. He might realize that he needs to be more careful with his use of sealing techniques in the future. This realization could lead him to seek out different types of training or knowledge, which would then shift the direction of the plot towards a more self - reflective and strategic Naruto.
If Naruto gets sick after the sealing, it can slow down the progress of the story. His allies might have to focus on taking care of him instead of moving forward with their plans. This gives the enemies more time to prepare or carry out their own evil schemes.
The sealing of Nagato can be a catalyst for character development. Naruto, for example, who has always been about redemption and understanding, might struggle with the idea of Nagato being sealed. He could question whether it's the right thing to do or try to find a way to rehabilitate Nagato instead. This internal conflict within Naruto can shape his actions and decisions throughout the fanfiction, and in turn, affect the overall plot as he tries to balance his beliefs with the situation at hand.
Her sickness could also be a way to develop relationships. Maybe Peeta has to take care of her, which could lead to a deeper emotional connection between them. Or it could make other characters show their true feelings towards her, whether it's loyalty or envy.
The sealing of Hashirama can also create new alliances. Clans that were previously at odds might come together to figure out how to deal with the situation. They might share secrets or techniques that were previously hidden in order to find a way to unseal Hashirama or at least mitigate the effects of his absence.
It can completely change the power balance. With two of the most powerful ninjas sealed, new characters may rise to fill the power vacuum. This could lead to new rivalries and alliances.
It can create a lot of worry among the Weasley family. They would then take care of Harry, which shows their family's warm - heartedness. This could also lead to some interesting interactions between Harry and the Weasley members, like Ginny might be more concerned and show her feelings for Harry more openly.
It could be due to the after - effects of the sealing on his internal energy balance. Naruto's body is used to a certain way of handling chakra, and the sealing might have disrupted that. His immune system, which is probably linked to his chakra in some way in the Naruto universe, could have been affected. For example, if the sealing was to contain a powerful and malevolent force, some of that 'bad energy' could have seeped into Naruto's own energy system, causing an imbalance and resulting in sickness.
One possible reason could be the strain on his body from the sealing process. Sealing powerful entities often takes a toll on the user's chakra and physical health. Maybe his chakra system was disrupted during the sealing, leading to internal imbalances that manifested as sickness.
It could make his friends more protective. Since Naruto is in a weakened state without his full chakra, his friends might be more concerned about him and try to keep him out of dangerous situations.
His early sickness could make him more determined. He might have faced a lot of challenges growing up due to his weakened state as a baby, and this could fuel his desire to become strong.