I don't know for sure, but I would assume the dark princess is one of the main characters. There might also be a villain, perhaps someone who wants to keep the princess from achieving her goals or someone who wants to use her power for evil. And there could be a sidekick or a mentor figure for the princess, like an old wizard or a brave knight who helps her along her journey.
Well, the central character is the dark princess. She might have a group of friends or followers. For instance, a group of rebels who believe in her cause and want to help her fight against the oppressive forces in the kingdom. There could also be a council of elders in the kingdom who have an impact on the princess's life. They might try to guide her, or they might try to restrict her actions because of her 'dark' nature. And of course, there could be an antagonist, like a powerful sorcerer who wants to rule the kingdom and sees the princess as a threat.
There are the princess, who is the unwitting subject of a strange and perhaps malicious test. The prince, who may be complicit in the rather dark plot against the princess. He might be more interested in fulfilling his mother's wishes rather than truly caring for the princess. And of course, the prince's mother, who is the mastermind behind this dark version of the 'princess and the pea' story, using the pea as a tool to judge and potentially reject the princess.
Since I don't know the exact 'dark crystal short story', it might have some original characters created just for this short story. However, if it follows the general Dark Crystal universe, there could be Gelflings like Jen and Kira as main characters. These Gelflings are often in the center of the stories, trying to save their world from the Skeksis or other threats. There could also be some important Skeksis characters if the story focuses on the power struggle in that world.
Often, there is a central character, perhaps a person in a spooky or isolated place like a schoolteacher or a traveler. This character is the one who has the encounter with the face in the dark. There may also be other minor characters who are mentioned briefly to set the scene, like colleagues or fellow travelers who are not present during the main event.
There might be a local fisherman. He would know the waters well, but still be in awe or a bit scared of the 'dark waters'. He could provide some local knowledge and a connection to the area around the water. He might also serve as a guide or a warning to other characters.
I don't know the main characters as I haven't read the story. It could be a lone traveler, or perhaps a group of friends who decide to take a walk in the dark.
I'm not sure as the details about the story aren't fully known. But usually in such a story, there would be a protagonist who is the one to encounter the face in the dark.
A group of friends could be the main characters. They might have a tradition of going out together after dark. The story could revolve around their adventures, like getting lost in an old part of town, or stumbling upon a hidden party that only takes place at night.
I don't know since I haven't read it. It could be a single protagonist, like a young woman who is alone in a creepy place and hears the whisper. Or it could have multiple characters, such as a group of friends exploring an abandoned building where the whisper occurs.
Since there are multiple 'dark tower short stories', the main characters can vary widely. In some, it could be the Man in Black, who is an important figure in the Dark Tower universe. He is mysterious and his actions often drive the plot. Another possibility is that a new character is introduced in the short story who becomes the main focus. This new character could be related to the events or characters in the main series in some way, for example, a descendant of a character from the main novels or someone who has a special connection to the Dark Tower itself.
There might also be some secondary characters. For instance, if the story is set in a small town, there could be neighbors or friends of the protagonist. They might either be involved in the mystery of the voice too, or they could be used as a contrast to the protagonist's experience. Say, the neighbors don't believe the protagonist when they say they heard a voice in the dark.