I'm not sure specifically as I haven't read it. It could potentially be about the adventures or stories related to a doorkeeper in a very visual and graphic novel format.
Well, without having read the 'doorkeeper graphic novel', it might be centered around the character of the doorkeeper. Maybe it tells the story of his daily life, the people he meets while guarding the door, and the secrets or mysteries that are associated with the door he is in charge of. It could also involve some sort of fantasy elements like the door leading to different magical worlds or something.
The 'doorkeeper graphic novel' could be about many things. It might explore the idea of a doorkeeper as a symbol of protection or a barrier. The graphic novel might show his past, how he became a doorkeeper, and what challenges he faces in his role. It could also include other characters who interact with the doorkeeper, such as those who try to break in, those who seek his help, or those who are just passing by. There could be a whole world built around this doorkeeper character, with different locations, events, and relationships all depicted through the art and story of the graphic novel.