Yama, twin–alternately the restrainer, is a Hindu god of death mentioned in Vedic texts. He is either the son of Vavasvan and Saranju, or Surya and Sanjna, and his consort is Dhumorna or Yami. Yama is also the judge of the dead and his twin sibling Yami is the goddess of death. When Krishna is perceived as the embodiment of the cosmos, his eyeteeth are Yama. He evolved into a dikpala, or guardian, of the southerly direction. The black buffalo is his animal, and his color is black.
This god is regarded as a guardian deity by the Buddhist-Lamaist (Tibet), one of a group of the dharmapala with terrible appearance and royal attire who guards the Dalai Lama. The deity stands upon a man. His colors are red, blue, white, or yellow; and his attributes are most commonly a noose and staff, but also club, net, shield, sword, trident, and two tusks. A.G.H.
Jordan, Michael, Encyclopedia of Gods, New York, Facts On File, Inc. 1993, pp. 291-292