This exceptional fine black-ground painting (Tib. nag.tang) on silk most likely represents Ma.ning.nag.po Mahakala or the Black Eunuch, with a human heart in his right hand and a garland of hearts around his neck. This very rare form of Mahakala presides over all the Dangerous and Enlightened Protectors of the Nyingma.pa school. The few known painted representations show him with specific high and wavy hirsute ornamented with curling snakes. Scholars have suggested that his name refers to transcending duality, thus beyond the male or female concept, and standing for the enlightened mind. He is surrounded by several divinities belonging to his retinue, including Rahula. The latter can be recognized by his snake-body.
The superb line drawing and contrasting colour use on a silk background makes this painting a rare testimony of the fine workmanship of Tibetan artists.