I mean that seems like an entertaining premise where a protagonists is literally insane due to some bullshit trauma and hunting a supernatural killer. Have the protagonists mind be a group therapy session and slowly as he fucks up the chairs become empty, but he's more levelheaded because the trauma he's clinging onto is purged from his conscious and subconscious mind. We might have a shitty pulp comic on our hands.
Superfluous conflict would be his imaginary friend personality that was created when the main character was abused being afraid of dying, but ultimately fulfilling it's role by giving it's identity in order to protect the protagonist, you'd probably have to make it some kinda superhero or cowboy kinda guy to really manipulate peoples emotions because of how pathetic the protagonist would have to be. Issue is do you want to go the route of the cops being oblivious to the supernatural or some gay secret society bullshit or just the fact that magic is more or less a lost art that the authorities are aware of, but it's ultimately less useful than a gun.
EDIT: You could probably play that each personality was created to cope with something. Superhero/ Cowboy was to escape early childhood trauma, Thugish guy for prison, servile asskisser for keeping a job after getting out of prison. You'd be basically be copying shit like Split, Death Note, Jekyl/Hyde, and other bullshit. If I was good at writing dialogue I'd probably do this in my spare time between looking for a 2nd job.
