The two-armed Mahakala is most popular in the Newar Buddhism of Nepal. In the Mahakala Tantra, he is described as the form by which the sufferings of sentient beings are removed. Such images are placed in the entrances to many bahals (monasteries) with Mahakala on the left as one enters and Ganesha on the right.

Mahakala (AD1661) Stone Svayambhu Mahachaitya Museum, Nepal	The two-armed Mahakala is most popular in the Newar Buddhism of Nepal. In the Mahakala Tantra he is described as the form by which the sufferings of sentient beings are removed. Such images are placed in the entrances to many bahals (monasteries) with Mahakala on the left as one enters and Ganesha on the right.
Kartridhara Mahakala	He may also be holding his chopper aloft in which case he is referred to as 'Kartaridhara (Holder of the Chopper) Mahakala.'
Mahakala of the Black Cloak Tibet. circa 16th century	Finally, there is the misshapen and squat two-armed, black-cloaked (Bernag chen) Mahakala, who is particularly the protector of the Karma Kagyu School.

Mahakala is typically black in color. Just as all colors are absorbed and dissolved into black, all names and forms are said to melt into those of Mahakala, symbolizing his all-embracing, comprehensive nature. Black can also represent the total absence of color and signifies the nature of Mahakala as ultimate or absolute reality and transcendence of all form.

The most notable variation in Mahakala's manifestations and depictions is in the number of arms, but other details can vary as well. For instance, the two-armed Mahakala was transformed from the first Buddha, Ardhalma and is worshiped for his spiritual wisdom. The four-armed Mahakala was transformed from the Sambhogakaya Buddha. The six-armed Mahkala comes in two forms : one white and one black. His white form helps one attain riches and a long life. His black form was transformed from Avalokitesvara and helps people conquer any obstacles on their path to enlightenment.

The two-armed Mahakala called Bernakchen is a protector of the Karma Kagyu school. It is often thought to be the primary protector, but it is actually the main protector of the Karmapas specifically.

This protective deity is described as figures possessing stout bodies, short but thick and strong limbs. His flaming hair, decorated with a crown of skulls, rises from his forehead, while a circle of flames dance around him. His face possesses a typical wrathful expression. The mouth is contorted to an angry smile from its corners protrude long fangs. The protruding, bloodshot eyes have an angry and staring expression and usually a third eye is visible in the middle of the forehead.

In his right hand, he holds a chopper, which symbolizes the cutting through of negative patterns such as aggression, hatred, and ignorance. In his left hand, he holds a skull cup, a ritual element typically filled with blood or human brain matter. He is seen standing on the corpse of two human bodies, thus symbolizing the death of negativities and the complete uprooting of negative patterns to such a point that, like a dead body, they will not come to life.

Mantra of Mahakala