The Hell as depicted in Chainsaw Man is the location from which devils - manifestation of mankind's fears - originate.
Devil return to hell after they die on Earth. The embodiment of the fear of Hell is the Hell Devil which can transport individuals to hell from Earth and vice versa.
One portion of Hell appears to be a grassy, flowery field with hills, with countless doors parallel in the sky. It is unknown whether there is more to Hell beyond this area that has not been seen.
