I would discribe the role of Ka Lee in Mr. Vampire (1985) as 'nightwatch' (or how do you call such a person in English?).

This suggestion must be replied by an English native speaker editor.

"Night Watchman"? I can't remember the film well enough to know how well that fits

He is the man who walks around at night with a latern and tells what time it is. Pauline Wong asks him to take advantage of her. Then he is beaten up by Chin Siu Ho.
Do you remember now?