The Mahakala Buddha is a Dharmapala, or "protector of dharma", who resides in the fourth hierarchy of deities, and is most associated with the Vajrayana Buddhism.

Mahakala’s Sanskrit meaning comes from its roots of "Maha", or "great", and "kala", meaning "black". Tibetans generally tend to refer to Mahakala as "the protector". He is also referred to as "Lord of the Tent" by the nomadic Tibetans, who often call upon Mahakala to protect them in their tents Mahakala is called Daheitian by the Chinese, and Daikokuten by the Japanese.

Mahakala is primarily believed to be an emanation of Avalokiteshvara (the Tibetans’ Chenrezig), or Chakrasamvara. While some consider Mahakala a wrathful diety, others believe he utilizes wrath or aggression only when more benevolent means fail. Mahakala could be likened to any overwhelming source of regeneration – the process of regeneration may be frightening, but real transformation can bring about much more fulfilling growth than their "easier" counterparts. Much like any "protector", or paternal image, Mahakala presents beings with challenging yet fair opportunities for real spiritual evolution. While Mahakala can be fierce, aggressive and destructive at times, his main motivation is to destroy ignorance.

Mahakala takes different forms in different lines of Buddhist teachings. He is generally black in color because his all-encompassing vibration embraces all colors and varieties in existence. Transversely, his black color can represent the absence of all colors, having essentially the same connotation as the former. Mahakala is widely represented to bear a crown of five skulls, which represent the metamorphosis of the five kleshas into the five wisdoms. The mastery of these five principles are: 1) ignorance transforms into the wisdom of reality, 2) pride becomes the wisdom of sameness, 3) attachment becomes the wisdom of discernment, 4) jealousy becomes the wisdom of accomplishment and 5) anger becomes a mirror like wisdom.

Though most depictions of Mahakala have certain similarities, there are several differences to be had as well. Mahakala is often depicted having two, four or six arms – again, depending upon the Buddhist sect.

The two-armed version of Mahakala emanates from the original Buddha, and embodies great spiritual wisdom.

Sambhogakaya produces the four-armed version of Mahakala. Each of his four arms are reputed to perform the following four acts of positive karma: pacifying sickness and troubles, expanding good qualities and wisdom, attracting people to the teachings of the dharma, and destroying ignorance, doubt and confusion.