If this is a story about a historical Charles, key elements might be his upbringing, his family background, and the historical context in which he lived. For instance, if it was Charles Darwin, his upbringing in a scientific - minded family and the Victorian era's attitude towards religion and science were important elements. His travels on the Beagle and his observations during those trips were also crucial to his story of developing the theory of evolution. Without knowing the specific Charles, we can only list these as possible key elements.
One key element is his ability to deceive. He was able to charm people easily. Another is his choice of victims, mainly Western tourists. And of course, his brutal crimes which included murder and robbery.
One key element could be family. Christmas is a time for family gatherings, and Prince Charles would likely have his own family traditions. Another might be charity work. As a public figure, he may engage in various charitable activities during Christmas.
One key element is the difference in their backgrounds and ages. Charles was much older and had grown up in the royal environment. Diana was a young commoner. Another element was the pressure of the public eye. Their every move was watched. Also, Charles' relationship with Camilla was a significant factor that affected the course of their love story.
The key element is his passion for makeup. Without that, he wouldn't have started sharing his looks.
One key element is the island setting. It provides the isolated and spooky backdrop for the story. Another is Charles itself, the demonic train. Its existence as a menacing force is central. Also, the fear of the people on the island towards Charles is a key part.
One key element is his criminal nature. He was a murderer. Another is the voodoo aspect which is central to his ability to transfer his soul. And of course, his transformation into the Chucky doll which makes his story so unique in the horror genre.
As I don't know the specific story, I can't say for sure. But common key elements in a story about two people could be their relationship, like whether they are friends, family or in a romantic relationship.
One possible key element could be friendship. In high school, making friends is important, and James Charles might have had a group of friends who influenced him or supported him.
The key elements are his life as a serial killer and his knowledge of voodoo.
One key element is the setting. The signalman's post is a desolate and lonely place, which immediately sets a creepy mood. Another is the appearance of the apparitions. Their sudden and unexplained presence is terrifying. Also, the signalman's increasing paranoia as he tries to figure out what the apparitions mean adds to the horror.