He could also develop a stronger sense of empathy. As a spirit, he was somewhat detached from human emotions. But as a human, he has to experience them firsthand. This could lead to him becoming more caring and more involved in the lives of those around him.
Well, at first, Jack Frost as a human might be very confused. He could be disoriented by all the new sensations and the lack of his ice powers. But as time goes on, he might start to appreciate the simple pleasures of being human, like the warmth of a hug or the taste of hot chocolate.
One idea could be that Jack Frost turns into a human to experience the warmth of human emotions. He might find himself in a small town during winter. As a human, he discovers the joy of a hot drink on a cold day, something he never truly understood as a spirit. He could also fall in love with a local girl who is kind - hearted and loves the winter. This newfound love makes him question whether he wants to return to his former state or stay human forever.
For Elsa, the kiss might make her more open and less afraid. She has always been a bit isolated because of her powers. Jack Frost, being more carefree, could influence her to be more confident in herself. For Jack, he could become more responsible. He might start to think about protecting not just winter for the fun of it, but also for Elsa and the people she cares about.
Albedo might become more empathetic. As a girl, he could experience different social interactions and emotions. He might also become more aware of his appearance and how others perceive him. For example, he could start to care more about his clothing and grooming.
He could develop more empathy towards humans. Since he's in human form, he gets to experience life from their perspective. This could make him more understanding and less likely to use his powers recklessly.
He could transform into a human and use his powers in unique ways. For example, he might be able to create ice sculptures with his bare hands more intricately than before. Since he's now in human form, his connection to winter is still there but expressed differently.
Well, for Loki, his development could be about finding a new purpose. Instead of just causing chaos, he has someone to care for. He might become more selfless. The baby Frost Giant, on the other hand, could start to show signs of leadership as it grows. It could learn from Loki's cunning and use it for positive things in the future, like uniting the Frost Giants in a more harmonious way.
Well, they might start off with some confusion. Jack, with his mischievous nature, could play a little trick on Hiccup which Hiccup might not appreciate at first. But then they would start to talk. Hiccup would probably be full of questions about Jack's powers and his origin. Jack would be equally interested in Hiccup's relationship with Toothless and the other dragons.
Naruto would definitely have a huge character development. At first, he might be confused and a bit frustrated about the change. But as time goes on, he could learn to embrace his new form. He might become more empathetic towards the female characters in the village, understanding the challenges they face. Sakura, on the other hand, would feel guilty for the accidental transformation. She would strive to find a way to turn Naruto back, which could lead to her developing her medical ninjutsu skills further.
Obviously, Jack Frost is the main character as the story is about his transformation into a dark version of himself. But there could also be other characters from the original Jack Frost lore, such as the Guardians like North, Bunny, and Tooth. They would likely play important roles, either trying to save Jack from his dark path or being forced to oppose him if he becomes too dangerous.
Another plot could involve Jack Frost being lured into the darkness by an external force, like a shadowy entity. This entity might promise him more power and control over his existence. As he succumbs to it, his appearance could change, his eyes turning a deep, cold black, and his ice becoming darker and more dangerous. His personality would shift from the carefree spirit we know to a brooding and vengeful being.