Damon Macready was an accountant living a boring and repetitive life with a wife who hated him and a daughter whom he cherished. Relying on his love of comic books, he sought to be someone who made a difference against crime, fancying himself as a real life superhero vigilante. To this end, he began to train both himself and his daughter in every lethal field of combat known to man. He brainwashed her with a fictional origin story that stated her mother was killed by frustrated mafia soldiers led by John Genovese, thus creating a motive and a target for both of them. He named himself Big Daddy and his daughter became the katana wielding butcheress known as Hit-Girl. Whilst he was training her, he began his war on crime, spending ten years fighting criminals prior to his allegiance with Kick Ass. He wears a Batman-like costume with kevlar reinforcement and is highly skilled with all manner of weaponry. In combat, he uses A Beretta 92 handgun, a collection of combat knives, and several hand grenades.
http://www.comicvine.com/big-daddy/29-57159/Vic Mackey's morality is a classic example of selfish consequentialism. Mackey feels that his actions are justified if they produce the best consequences for himself and those close to him. While he had a solid status as a family man, he committed adultery with several women, including his fellow officer Danielle "Danny" Sofer. Mackey's personality is often viewed as amoral or machiavellian, believing that the ends justify the means. However, this ultimately led to his downfall, which he narrowly avoided until the very end of the series.
His brutality is usually directed towards criminals whom he considers deserving of their harsh treatment at his hands-i.e. rapists, child molesters and mass murderers. Even when he has broken these laws himself, he has often justified it to himself by doing so in order to solve what he regards as more serious crimes. For example, in the First Season finale episode, Vic cornered a teenaged murder witness and threatened to plant crack cocaine on him unless he violated the neighborhood code of silence and revealed who murdered two police officers, proving that he will hurt the innocent if it suits his needs.
http://en.wikipedia.org/wiki/Vic_Mackey