Every year on the anniversary of the battle, The Butcher would celebrate this victory and invite a select few. Many years later, the tradition would continue, and one mysterious young man would appear and hope for an invitation of his own. His name is Amsterdam (Leonardo DiCaprio) and he is the Preist's son, hell-bent on revenge. His plan is to get close to The Butcher and gain his trust, then kill him in front of everyone at the annual celebration. In the meantime, however, Amsterdam would begin to understand why so many support the Natives and their shrewd practices. In the streets, many things do not come easily, but they come easier when you're on the right side.
For Bill the Butcher, he was a businessman with political ties, and he was a merciless fighter and leader of his own giant gang. He did have some sense of honor and his growing admiration for Amsterdam would show his softer side. Indeed, Amsterdam's personal vendetta would become vastly more complicated. The Butcher is still the Butcher, though, and his viciousness is undeniable and unrelenting when challenged. In the end, Amsterdam's victory is somewhat hollow because of how deep the Butcher cut psychologically. For a young man who saw his father cut down when he was a boy, to kill the only other man to treat you like his son seems, well, foreign.
Source:movievillains.com