Since I don't know the exact 'Christmas Trolls Story', the main characters could be the trolls themselves. There might be a leader troll who makes decisions for the group.
Trolls themselves are the most common characters. They can be of different sizes and temperaments. Sometimes there are also human characters who are the victims or challengers of the trolls.
Poppy is likely to be one of the main characters. She's always positive and loves to spread happiness. Branch, who is a bit more cautious, might also be a main character. They are important in the Trolls world and would play big roles in the novel.
They might get really excited and start comparing it to their own experiences in the Trolls world. Maybe they'll laugh at the funny parts or feel inspired by the creative interpretations in the fanfiction.
Well, in fantasy fiction, cave trolls differ from other trolls in several ways. For one, their physical features might be more suited to cave living. They could have a thicker hide to protect against cave - related hazards. In terms of behavior, cave trolls are usually more territorial about their caves. While other trolls might be more nomadic or have a wider range of movement. Also, the diet of a cave troll is likely to be more limited to what is available in or near the cave, such as bats or underground fungi, as opposed to other trolls that might have a more diverse diet depending on their habitat.
I think Poppy and Branch are the main ones. Poppy is usually very positive and outgoing, while Branch is more cautious. In the junior novel, they would likely lead the adventures during the world tour.
Typically, the main characters would be the ones from the original Homestuck. So, John Egbert would likely be one of the main characters. He's known for his adventure - seeking nature. Jade Harley might also be a main character, with her unique abilities and her connection to the game's mechanics. Dave Strider, with his cool - guy attitude and his role as a time - traveler of sorts, would probably be a central figure as well.
John Egbert is often a popular choice. His laid - back and somewhat naive personality can lead to some interesting character development in the Hunger Games setting. He might start off as an underdog but grow into a formidable opponent as the story progresses.