Originally Posted by the last son
How does no one not know who the joker really is? I mean wouldn't someone see him see the scars and say hey that's whoever from wherever. I mean someone would know who he is. He didn't just live in the sewers his whole life. Childhood friends whatever.
Unless he grew up on the streets and lived in street gangs. Such theory and background for Ledger's Joker was presented in one of the post TDK stories
In there he killed his parents when he was a kid and lived on the streets. Such background presents a plausible explanation for having no name and no identity