'Heruka' a Tantric Buddhist Term with Many Different Meanings
Heruka is a Sanskrit word that has a number of different meanings depending on the Tantra literature in which it is defined. In the Tibetan language the word heruka is translated as drag tung which means blood drinker. This translation of the Tibetan word is more descriptive than it is etymological. When the term heruka is used in art and iconography it generally has three different meanings as found below.
In the Nyingma (Old) Tradition of Tibetan Buddhism Heruka generally refers to any male-meditational deity, wrathful in appearance, typically with three faces, six arms, four legs, wings and a consort. There are eight famous and specific Nyingma Heruka deities originating with the Eight Vidyadhara teachers of the early tradition. Some deities with a semi-peaceful - semi-wrathful appearance, arising from specific Revealed Treasure Traditions, may also be referred to as Heruka.
In the Sarma (New) Traditions of Sakya, Kagyu, Jonang and others, the term Heruka is typically understood to mean any complex Anuttarayoga male-meditational deity, peaceful or wrathful, that appears in a simplified form with one face, two arms and a consort.
In the Gelug Tradition (also belonging to the Sarma) the term Heruka is almost exclusively used to refer to the complex meditational deity Chakrasamvara in all aspects, complex with multiple faces and arms or the simple with one face and two arms, and all the variations in between.