Ma ye, and Niu ye (Father Bull) are inseparable companions of Jama, the god of Hell. They assist him, in their role of policemen, when he has to sit in judgement on the souls of the dead. We can see from their extraordinary appearance - with animals' heads - that these gods originated in Buddhist beliefs. After Buddhism came to China, several of the Indian deities found their way into Chinese popular religion, where they acquired a name and function suited to the Chinese world of the gods.