A notable feature of Tibetan Buddhism is the emphasis on wrathful deities, often alternative manifestations of normally peaceful deities. True to their name, in Tibetan art, wrathful deities are presented as fearsome, demonic beings adorned with human skulls.
Wrathful deities can be divided into several categories:
The Herukas (Tb. tRak-thung, lit. "blood drinker"), which are enlightened beings that adopt fierce forms to express their detachment from the world of ignorance.
The Protectors (Sanskrit. pala), usually subdivided into three categories:
Dharmapalas or "Protectors of the Law" are bodhisattvas, beings one step from enlightenment, which have taken a vow to assist other sentient beings on their path
Lokapalas or "Protectors of the World" are guardians of the four cardinal directions
Wrathful Guardians of Buddhism - Aesthetics and Mythology
Their faces possess a typical wrathful expression: the mouth is contorted to an angry smile, from its corners protrude long fangs often said to be of copper or iron -, or the upper teeth gnaw the lower lip.
compassion for all sentient beings and the wrath of an asura....