The real “painter” is the Yuen Wen, the big boss of the counterfeiting group.
Chow’s character is fictional, created by Lee Mun, but it is actually the real description of Lee Mun himself. Where as Lee Mun’s character in his own “story telling” is completely fictional.
Sau Cheng was rescued by Lee Mun during the fire-gun fighting and she was given plastic surgery to become Yuen Wen, so that the real Yuen Wen can go behind the scene to run the business.