I tried to google this but all I saw were many religious topics.
The story was set in a place called Sundownia. It was a special afterlife for suicides. Civilization was completely normal. You could go to a bar and drink but you would never get drunk.
Most people didn't know they were dead but a few did and they had super powers because they knew they were dead.
The people who knew they were dead looked for each other and chose up sides to fight each other because they were already dead and weren't going to die. There was just nothing else to do.
The people who didn't know they were dead never noticed that the others could fly or morph into a motor cycle.
This could have been a graphic novel. This post makes me kind of ashamed of myself. I have always been a voracious reader but I never retain the meta like authors or in this case even the media used.