As we lack information about 'the black door story', the main characters could be numerous. It could be a detective - like character who is trying to solve the mystery of the black door. Maybe there are some local villagers who are scared of the black door and its implications. There could also be a shadowy figure that guards the black door, and the story could revolve around the interactions between these potential characters.
Not having read the novel, I can only guess. There might be a brave explorer type of character who is drawn to the black door. There could also be a wise old mentor figure who tries to warn the protagonist about the perils of the black door. And perhaps there is an antagonist who wants to use the black door for their own evil purposes.
Since I'm not acquainted with this novel, I can't name the main characters. You might want to check the book's description or other readers' comments.
There could be a curious child as one of the main characters. This child is always exploring and it's their inquisitiveness that leads them to the secret door.
Since I don't know the exact 'door man story', it could be the doorman himself as the main character. There might also be some regular visitors like a kind old lady or a busy businessman who interact with him a lot.
I don't know since I don't have details about this specific 'the secret door story'. It could be a young adventurer, an old wizard, or just an ordinary person who stumbles upon the secret door.
I'm afraid I can't name the main characters without more information about the 'the door game story'. There could be a brave hero, or a group of friends, or even some magical creatures, but it's all speculation at this point.
The white teen might be a bit of an outcast among his peers, looking for something different and finding it in the black goddess. She, on the other hand, could be the popular girl in the neighborhood, known for her beauty and charm. There could be a best friend for the white teen who gives him advice on how to approach her, and for the black goddess, there could be an older sister who warns her about getting involved with someone from a different background.
Obviously, the boy next door is one of the main characters. There might also be the narrator, who could be a neighbor or someone who has a close relationship with the boy next door.
Perhaps the main characters are hunters or trappers who find themselves in a situation where wolves are at their door. They could be experienced outdoorsmen who have to use their skills to deal with the approaching wolves. There might also be local villagers who are affected by the presence of wolves near their homes and are the central figures in this true story.
As I don't know the story, it could be the parents in the family next door, their children, or maybe even the family pet.