In terms of appearance, the wrathful deities look even more sinister than ordinary demons. People may easily mistake them for the deities of an evil cult if they do not know what the wrathful deities represent. For example, there is a blazing fire at the back of the wrathful deities and Dharma protectors, but white light at the back of the peaceful deities. Actually, fire here represents wisdom of the buddha—just like fire can burn down everything, so can wisdom cut through all afflictions. In addition, wrathful deities hold in their hands not bowls but human skulls, and the skulls contain not wholesome foods like fruit and grains but red blood. What does it mean? Blood represents desire, and desire is the main cause of ending up in the three lower realms. Drinking the blood represents eradicating completely the desire for samsara.

- Quote from Gateway to the Vajrayana Path, "The Parable of a Black Snake"