Wrath

Batman had two different enemies named Wrath. The first, whose real name was never disclosed, had an anti-Batman origin very similar to Prometheus. One night, while sneaking out of their apartment to avoid paying rent, Wrath's parents were mistaken for burglars by the police and shot dead. Wrath became obsessed with taking revenge on police and other law-enforcers, which lead to a career as an assassin.

The second Wrath, Elliot Caldwell, was an orphan, one of five abducted by the original Wrath to become the equivalent of Robin, but Caldwell was the only one of the five to survive Wrath's training. Eventually, Caldwell took over as the new Wrath.

Pros: The purple costume is kind of cool, though it might not work in the Nolan-verse. Wrath's anti-Batman origin isn't as contrived as Prometheus'.

Cons: It's still a little contrived. And he's a total no-name villain.

How I'd do it: Show his parents' murder, then just cut straight to the pimpin' purple costume.

Casting Guesses: It could be anyone, so I'll say Clive Owen, cause I like him.

Verdict: Nah. If they announced Wrath, even most dedicated fanboys would be rushing to google to figure out who he is.