The Bronze Fist is one of the Main Family strongest move. If you master this technique you could pick up and destroy an eight ton truck using just your bare hands.
The Shinkyokushin Dojo where this technique resides gets attacked by robots. Aran and the disciples show up and stop the robots from destroying Lu-Chang and the technique. In doing so Aran uses some kind of technique that steals technique by draining them from others on Lu-Chang. Thus Aran otainss the Bronze Fist.