The Two Face

You, a hero, male or female, used to fight a man who was mostly a pushover, always trying to defeat you, but his extremely complicated plans never worked. So he turned to experimenting on himself. One day, when he injected himself with a highly unstable serum, is when he became the Two Face. Both his face and personality split into two, the old villain and the new psychotic and deadly one. He seems to be internally struggling, perhaps ypu can help him? Or just leave him to his fate to rip himself apart.