In Buddhism, lokapāla are one of two broad categories of dharmapāla (protectors of the Buddhist religion) -the other category being Wisdom Protectors. In China, "each is additionally associated with a specific direction and the Four Heraldic Animals of Chinese astronomy/astrology, as well as playing a more secular role in rural communities ensuring favorable weather for crops and peace throughout the land...Easily identified by their armor and boots, each has his own magic weapon and associations."[1] Their names are (east) Dhrtarastra, (west) Virupaksa, (north) Vaishravana, and (south) Virudhaka.
In Tibetan Buddhism, many of these worldly protector deities are indigenous Tibetan deities, mountain gods, demons, spirits or ghosts that have been subjugated by Padmasambhava or other great adepts and oath bound to protect a monastery, geographic region, particular tradition or as guardians of Buddhism in general. These worldly protectors are invoked and propitiated to aid the monastery or Buddhist practitioner materially and to remove obstacles to practice. However, since they are considered to be Samsaric beings, they are not worshiped or considered as objects of refuge.[citation needed]
Kalsang, Ladrang (1996) The Guardian Deities of Tibet Delhi: Winsome Books. (Third Reprint 2003) ISBN81-88043-04-4
Linrothe, Rob (1999) Ruthless Compassion: Wrathful Deities in Early Indo-Tibetan Esoteric Buddhist Art London: Serindia Publications. ISBN0-906026-51-2
De Nebesky-Wojkowitz, Rene. (1956) Oracles and Demons of Tibet. Oxford University Press. Reprint Delhi: Books Faith, 1996 - ISBN81-7303-039-1. Reprint Delhi: Paljor Publications, 2002- - ISBN81-86230-12-2