Mahakala is the wrathful form of the gentle and compassionate Avalokiteshvara Bodhisattva. In Tibetan iconography he is usually black, although he appears in other colors as well. He has two to six arms, three bulging eyes with flames for eyebrows, and a beard of hooks. He wears a crown of six skulls.
Mahakala is the protector of the tents of nomadic Tibetans, and of monasteries, and of all Tibetan Buddhism. He is charged with the tasks of pacifying hindrances; enriching life, virtue and wisdom; attracting people to Buddhism; and destroying confusion and ignorance.
Yama is lord of the Hell Realm. He represents death.
In legend, he was a holy man meditating in a cave when robbers entered the cave with a stolen bull and cut off the bull's head. When they realized the holy man had seen them, the robbers cut off his head also. The holy man put on the bull's head and assumed the terrible form of Yama. He killed the robbers, drank their blood, and threatened all of Tibet. Then Manjushri, Bodhisattva of Wisdom, manifested as Yamantaka and defeated Yama. Yama became a protector of Buddhism.
In art, Yama is most familiar as the being holding the Bhava Chakra in his claws.
Yamantaka is the wrathful form of Manjushri, Bodhisattva of Wisdom. It was as Yamantaka that Manjushri conquered the rampaging Yama and made him a protector of the Dharma.
In some versions of the legend, when Manhushri became Yamantaka he mirrored Yama's appearance but with multiple heads, legs and arms. When Yama looked at Yamantaka he saw himself multiplied to infinity. Since Yama repesents death, Yamantaka represents that which is stronger than death.
In art, Yamantaka usually is shown standing or riding a bull that is trampling Yama.
Hayagriva is another wrathful form of Avalokiteshvara (as is Mahakala, above). He has the power to cure diseases (skin diseases in particular), and is a protector of horses. He wears a horse's head in his headdress and frightens demons by neighing like a horse.
Vaisravana is an adaptation of Kubera, the Hindu God of Wealth. In Vajrayana Buddhism, Vaisravana is thought to bestow prosperity, which gives people freedom to pursue spiritual goals. In art, he is usually corpulent and covered in jewels. His symbols are a lemon and a mongoose, and he also is a guardian of the north.
Palden Lhamo, the only female dharmapala, is the protector of Buddhist governments, including the Tibetan government in exile in Lhasa, India. She is also a consort of Mahakala. Her Sanskrit name is Shri Devi.
Palden Lhamo was married to an evil king of Lanka. She tried to reform her husband, but failed. Further, their son was being raised to be the destroyer of Buddhism. One day while the king was away, she killed her son, drank his blood and ate his flesh. She rode away on a horse saddled with her son's flayed skin.
The king shot a poisoned arrow after Palden Lhamo. The arrow struck her horse. Palden Lhamo healed the horse, and the wound became an eye.
Tshangspa is the Tibetan name for the Hindu creator god Brahma. The Tibetan Tshangspa is not a creator god, however, but more of a warrior god. He usually is pictured mounted on a white horse and waving a sword.
In one version of his legend, Tshangspa traveled the earth on a murderous rampage. One day he attempted to assault a sleeping goddess, who awoke and struck him in the thigh, crippling him. The goddess's blow transformed him into a protector of the dharma.
Begtse is a war god who emerged in the 16th century, making him the most recent dharmapala. His legend is woven together with Tibetan history:
Sonam Gyatso, the Third Dalai Lama, was called from Tibet to Mongolia to convert the warlord Altan Khan to Buddhism. Begtse confronted the Dalai Lama to stop him. But the Dalai Lama transformed himself into the Bodhisattva Avalokiteshvara. Witnessing this miracle, Begtse became a Buddhist and a protector of the Dharma.
In Tibetan art, Begtse wears armor and Mongolian boots. Often he has a sword in one hand and an enemy's heart in the other.