Why does Ma Pan's father have a Kirin tattoo?

The tattoo of the character is because it has the effect of resisting witchcraft.

It is mentioned in the novel "Notes on Grave Robbery" that there is a custom where Ma Pan is located. Tattoos are used to prevent people from getting sick. A special medicine is boiled into liquid to tattoo children. As long as the person with this tattoo is sick, the tattoo will change. Later, a Feng Shui gentleman came here, and he changed the tattoo of the local people into Kirin.