It could be considered fiction. 'No Longer Human' by Osamu Dazai is often classified as a work of fiction. It tells a fictional story through the protagonist's experiences and internal struggles, though it may draw on some real - life emotions and themes.
The 'no longer human graphic novel' could potentially be a visual exploration of the psychological and emotional turmoil of the characters. It might use illustrations to depict the sense of disconnection from humanity that the title implies. Maybe it shows the protagonist's journey through a world where they feel out of place, with the art adding a new dimension to the story compared to the original text.
The 'No Longer Human' manga is based on the novel, but it does make some adaptations to suit the medium of manga. It retains the core elements and essence of the story though.
I don't have specific information on the main characters in this graphic novel. However, if it's based on the original 'No Longer Human', there might be a central character who is grappling with their sense of self and humanity.