Horse King and Ox King, detail. Late 19th-early 20th cent. Woodblock print. Luoyang, Henan Province, China. Asian Art Photographic Distribution (AAPD) (University of Michigan)
The image of the King of Horses, 馬王, an ugly ogre with three eyes and four hands, bearing various weapons of warfare, is occasionally found in wayside shrines. He is worshipped by horse rearers, and is usually accompanied by a similar figure, the King of Cows, 牛王。 These deities are supposed to be able to protect cattle from evil spirits and disease. The former has by his side a small model of a horse, and the latter that of a cow.
– Outlines of Chinese Symbolism & Art Motives, C.A.S. Williams, 3rd Revised Ed. 1976. Entry on: Horses.