It depends on personal preference. If you like visual storytelling, the manga might be more engaging as it shows the characters and scenes directly. But if you enjoy delving deep into a character's psyche through detailed text, the novel could be more appealing.
The medium - specific elements also play a role. The 'no longer human' novel uses only words to create the atmosphere, while the manga can use different art styles, shading, and paneling to set the mood. For instance, a dark and shadowy art style in the manga can enhance the sense of gloom and despair that the story often conveys, while in the novel, it's the language and the sequence of events that build up such emotions.
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.