This is a world where humans and ghosts coexist. People cannot touch ghosts, but ghosts can devour people.
The killer is a simple killer. As long as you pay enough money, he can kill for you.
The madman is a complicated madman. No matter you punch or kick him, he just won't leave.
The killer always lives for himself, but the madman always lives in other people's world.
A killer is always a killer, but sometimes a madman is not a madman.
"Just be good and don't block my way of making money."
"You'd better do well and don't block my way of survival."
Note: Crazy is not a description of his character, but a true lunatic.