is the outer form of Chaturmukha Mahakala. He is the special protector of the Guhyasamaja Tantra
and the 2nd main protector of the Sakya
Brahmarupa, a benign form of the wrathful deity Mahakala, is shown as a bearded nomadic ascetic, sitting on a corpse, wearing a bone apron, and holding a thighbone trumpet and a skull cup.
A protector of the Sakya school of Tibetan Buddhism
, he is credited with introducing the Hevajra