Maybe Jim is the protagonist who goes through various adventures and experiences. Or, he could be a key figure influencing the events in the story. Without more details, it's hard to say exactly.
In a fanfiction about them, perhaps there's a plot where Evil Jim manages to steal Jim's body or powers. Then Jim has to find a way to get them back. He could enlist the help of his friends, like Princess What - s - Her - Name. Meanwhile, Evil Jim, in Jim's body, starts to cause chaos in the universe. Jim has to outwit Evil Jim and regain his true form. This could involve a series of comical and action - packed adventures as Jim tries different tactics to defeat his evil self.
Judy is often shown as the one who is more idealistic in fanfic. She dreams big for Zootopia and wants to make it a better place for everyone. Nick is the realist. He helps Judy see the practical side of things. Their dynamic in fanfic is really interesting as they learn from each other. Nick teaches Judy about the underbelly of Zootopia while Judy shows Nick that there is good in the world worth fighting for.
They could be characters in a science - fiction setting. Nick could be an alien from a far - off planet who crash - landed on Earth, and Macy could be a scientist who is trying to help him get back home. As they work together, they develop a bond, and the kiss could be a way of showing their connection that transcends their different origins.
In the real Saint Nick story, the real Saint Nick was Saint Nicholas. He was a significant figure in early Christianity known for his acts of kindness and charity.
In a St Nick Day story, St Nick Day is significant as it's a time of giving and kindness. St Nick represents the spirit of generosity, so the day is about sharing and making others happy.
Nick and Nyx are likely the main characters in this horror story. They could be ordinary people who find themselves in a terrifying Christmas - themed situation.