It's Hercule Poirot. He often mentions relying on his 'little gray cells' to solve cases.
I'm not sure specifically what 'gray cells graphic novel' is about as there could be many with such a name. It might be about a mystery or a story that involves using one's intelligence ('gray cells' can refer to the brain or intelligence in a metaphorical way).
I don't know the main characters in 'gray cells graphic novel' as I haven't read it. It could be a lone hero, a group of friends, or even some extraordinary beings.
One possible fictional detective who was a janitor is in the mystery series 'The Unsung Sleuth'. In this story, the main character, Detective Mark, starts off as a janitor before solving complex cases.
I think it could be Sherlock Holmes in some alternate version. But usually, he doesn't live in a cemetery.
I can't think of one off the top of my head. Maybe you could give me a few more hints?
One such fictional detective who lives in a cemetery could be Victor Frankenstein. In some adaptations, he conducts his mysterious investigations among the tombstones.
Sherlock Holmes is one fictional detective who was known to solve crossword puzzles. His sharp intellect and logical reasoning made it possible for him to tackle such challenges.
My favorite fictional detective is Sherlock Holmes. He's just so brilliant and always manages to solve the most complex cases with ease.
I think I'm a bit like Sherlock Holmes - always observant and logical in solving mysteries.
I have no idea. Don't think I've come across such a detective.