Guan Yu was a famous general in the Three Kingdoms period. He was a great man before his death. Because of his high fighting capacity, he often helped Liu Bei accomplish many great things. Therefore, Guan Yu was called a warrior before his death, so after his death, people also called him a dead fairy. Guan can be highly summarized as follows: he was born a hero and died a ghost. When Guan Yu died, his deeds had a far-reaching impact on others, which made contemporary Hong Kong citizens have an indescribable affection for Guan Yu.
In fact, there is a legend about Guan Yu's death, that is, after Guan Yu's death, he made a lot of contributions before his death, so God listed Guan Yu as a fairy. Guan Yu's main duty is to put his hand into a passage in the sky, and some people have to go through Guan Yu's threshold if they want to become immortals, so Guan Yu's position is very important and his influence in society is very important.
Of course, these are all legends. What really matters is Guan Yu's own influence. It was under the constant spread and diffusion of ancient Central Plains culture that Guan Yu's influence was spread. Therefore, these policemen in Hong Kong seem to think that Guan Yu is the patron saint, and he can ensure the long-term stability of Hong Kong. Therefore, Guan Yu has become a belief in the hearts of these Hong Kong policemen, so this belief has been passed down and developed in Hong Kong.