Director Christopher Nolan said once that Harvey Dent’s transformation is the foundation story of the film..
He is going to transform into this damned ugly Two Face following an accident with some acid liquid:
(Click on a picture to enlarge it.)
“people don’t really know yet. Basically, when you look at Two-Face, you should get sick to your stomach. Being the guy under all that, well, that was a lot of fun for me. It’s like you would feel if you met someone whose face had pretty much been ripped off or burned off with acid. I can’t talk about it beyond that because I don’t want to give away too much of the plans by Chris.” (Source: LA Times)
A preview clip featuring Two-face has since been unveiled:
And it seems that the Joker (Heath Ledger) is the one who transformed Harvey Dent into Two Face by using some acid solution:
But Harvey Dent / Two Face bears a serious grudge against Batman the Dark Knight, not really against the Joker…
I’m going to have a nightmare tonight for sure. I hope Batman will come to rescue me!