Re: The Joker's background?
Joker's one of the few villains I can think of that truly benefits from having an anti-backstory. He's such an over-the-top, theatrical character that it's always a bit hard to swallow that he was ever a relatively average mob enforcer/crook/comedian/whatever. When you remove all of that (or at least make it very vague) it liberates him in a sense, to be less of an identifiable man and more of an anarchic counterbalance. Plus it plants for firmly in opposition to Batman, who of course has a very detailed and rich origin.
You do not fear death.
You think this makes you strong. It makes you weak.
How can you move faster than possible,
fight longer than possible,
without the most powerful impulse of the spirit:
The fear of death.