Kikokugai - The Cyber Slayer

This story takes place in an alternative future of Shanghai where money and power rules the city. Mafia groups hire Kung Fu masters and dominate the society. There are two types of Kung Fu masters, those who mastered their internal qi, and those who mastered their physical skills. The qi masters are able to output a stronger energy coming from their life itself, but it took a long time to master it. It was easier to just train their physical skills, but there was a limit to how strong a human body can be. So there were a balance of many average physical skill masters and few strong qi masters. However that balance broke when cybernetics came into play. Kung Fu masters would replace their body with robotic parts and attain a strength that a normal human can never achieve. That's how no one tried to become qi masters anymore when they can easily become powerful by using cybernetics, and qi masters decreased in numbers. The main character of the story Kong Taoluo, a qi master, used to be the top assassin of the leading mafia group. He was betrayed and killed, or at least he was supposed to be, but now he returns to city of Shanghai for revenge and for his sister... Source: VNDB