Hay Wong Hoi (also known as Johnny Weng in some translations) is the main villain in the 1989 John Woo action film The Killer.
He was portrayed by the late Shing Fui-on.
Wong Hoi is a ruthless Triad boss. He had his uncle murdered to take over the Triad and he also tried to kill the hitman, Ah Jong, because he was afraid that the hitman will tell the police that he was behind this. (Even though the hitman would never reveal he's clients names.) Ah Jong attempted to kill Hoi in retaliation for trying to kill him earlier.
Hoi survives, but is injured and scarred from the first attempt. Now even more paranoid and determined, He sends his entire gang to kill him. At the end, he uses Ah Jong's girlfriend as a hostage. Ah Jong manages to shoot him, but Wong Hoi frantically returns fire, killing Ah Jong and destroying his eyes in the process.
Wong Hoi goes to the police and, fearing for his life, begs to be taken into custody. However, Detective Li Ying saw Wong Hoi as a coward and he kills Wong in front of the police in revenge for killing Ah Jong but as a result, Ying is arrested shortly after.