Heruka is a principal Highest Yoga Tantra Deity (Tantric Buddha), who is the embodiment of indivisible bliss and emptiness.

Heruka has a blue-coloured body, four faces and twelve arms, and embraces his consort Vajravarahi. Their divine embrace symbolizes the union of great bliss and emptiness, which are one and the same essence.

For a detailed explanation of the practice of Heruka see the book Essence of Vajrayana, and the sadhanas Condensed Essence of Vajrayana, Essence of Vajrayana, Vajra Hero Yoga and Union of No More Learning, and the CDs Songs of the Heroes and Songs of the Vajra Father.