What's the movie title about a fighter raised from childhood?

I saw this movie a while back and now I can't remember the name of it to save my life. It's about an asian descent fighter whose mom was a prostitute or something and she was killed and the son was taken and raised to be this guys most insane kick-a** fighter and literally no-one in the world is even a relatively-close challenge for him. He barely talks thoughout the entire movie if any, I can't quite remember :/ He wheres a neck brace or something that allows him to know to unleash and kill people when taken off or something. Something happens where he is in a basement waiting for a signal from his boss and the blind piano player comes in and he gets distracted with the piano while his boss is pressing the signal like crazy getting the crap kicked out of him and the fighter finally realizes and rushes to his boss. The fighter ends up living with the blind piano guy and a little girl I think because he got in a car accident and he figured that everyone died besides him. But eventually one of the body guards who works for his boss finds him walking on the streets one day and they want him back or something. At the end he's fighting this body guard guy whose juicin' himself with like 10 syringes of ultra adrenaline juice or something. Hopefully the extreme amount of details will lead someone to give me a direct answer. :)