Since I'm not familiar with 'the black door novel', it's hard to say for sure. However, in many novels, there could be a group of characters. Maybe a family that has a connection to the black door, like a character who inherits a house with the black door and then starts to uncover its secrets. There could also be some side characters like neighbors who have heard rumors about the black door and add to the mystery and intrigue.
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.
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.
I'm afraid I can't say who the main characters are without more information about this 'a knock at the door novel'. However, it's common in such stories to have a protagonist who is affected by the knock at the door. There could also be the person or entity on the other side of the door. If it's a thriller, the main character might be a detective or an ordinary person caught up in a dangerous situation that starts with the knock.
I'm not aware of a specific 'a black door novel' so I can't tell you the author.
If it's based on the original 'A Wind in the Door', then Meg Murry is likely one of the main characters. She's a brave and intelligent girl. There may also be her brother Charles Wallace. He has special abilities and is an important part of the story. Another character could be Calvin O'Keefe, who is Meg's friend and helps her on her adventures in this strange world.
I don't know for sure since I haven't read it. But it could have a young protagonist who is curious about the wind in the door.
I'm not sure exactly who the main characters are without reading the novel. But it's likely to be the person who is considered the 'angel' and the one who notices this 'angel' quality, probably the neighbor or someone close to the so - called angel.
I don't know the main characters in 'lost door graphic novel' as I haven't read it. But they could be adventurers, like a brave young hero and his sidekick who are on a quest to find the lost door.
Since I haven't read the book, I can't say for sure who the main characters are. They could be anyone from an adventurous young person to an older, wiser figure.
Well, in a novel related to 'death's door', one might expect the main character to be someone on the brink of death. This character could be an old man reflecting on his life and the things he's done or left undone. There could also be a young character who has a near - death experience and has to come to terms with their own mortality at a very early age. And then there might be a character who has some sort of special ability or knowledge about death, like a shaman or a spiritual guide who helps the others understand what is happening as they approach death's door.