4wingedAngel
Explain bad?
He just went vigilante Two-Face is actually a deranged murderer.
Harvey Dent is the justice-seeking Prosecutor.
So when you add them together you get two opposit personalities trapped in one body, just like Dr. Jekyll and Mr. Hyde.
Dent didn't got vigilante, he became evil because the Two-Face personality was more prominent at the time.
If you notice in the comics and the such, Dent/Two-Face actually flips a coin to decide whether to act as Two-Face or Dent.
For example, Two-Face is about to shoot a police officer, but he flips a coin and it leads on heads. Heads represents Dent, since it's the Liberty dollar, and shows Lady Liberty, a symbol of freedom and justice.
Whereas the opposite side of the coin is scared, which represents the decay and mutilation that Two-Face embodies.
So if it lands Scars up, then they act as Two-Face and kill.
It's all about the bling-bling, to be frank. 8D