Believed to be performed in temples since 13th century, the masked dance of Mahakali – Mahakali Pyakhan - has legendary origins in a dream of the Malla king in which the goddess commanded him to show the battle between herself and the demons to the people - thus restoring peace in troubled times. Pyakhan means dance in Newari.

The story relates how the goddess, long after she had destroyed Mahishasur at the request of Brahma, Vishnu, and Mahesh, appears again to destroy the daityas Shumbha, Nishumbha and others, again at the request of the gods. King Jayasthiti Malla (1382-1395) is believed to have created dance dramas based on Durga Saptashati of Markandeya Purana and is said to have performed the dance of Mahakali in public himself.

The major performances of Mahakali Pyakhan are held at the time of Indra Jatra, a festival celebrated around September for eight days from the 12th day (Dwadashi) of bright half of Bhadra till the 4th day (Chauthi) of the dark half of Ashwin. Beginning with the installation of the Indradhwaja – a pole with a strip of white cloth - near the old Hanuman Dhoka palace in Kathmandu, Indra, Kumari, and Bhairav are worshipped, along with many rituals performed in the memory of ancestors and dead relatives to whom food and lighted lamps are offered. The living goddess Kumari and her attendants Ganesh and Bhairav are carried in a procession of three chariots on Chaturdashi, Purnima (14th day and full moon) and the last day of the festival. Masked dances and dance-dramas are performed in streets and squares by all male groups celebrating the victory of gods over demons. Sometimes the actors are possessed by the gods or demons they represent.

Mahakali Pyakhan is a tradition of Bhaktapur, 15 Kms east of Kathmandu where the royal Malla deity Taleju Bhawani temple is located. The performance begins with the three goddesses Mahakali, Kumari and Mahalakshmi and their attendants planning to attack the demons. Shumbha and Nishumbha, who are rejoicing in their victory over Indra. This is followed by battles of each goddess with the demons interspersed with the dances of the attendants. Beta (Vetala), the attendant of Mahakali has a yellow mask with a long tongue to lick blood from corpses. Kankal (Kawancha) skeletons are Kumari’s attendants who are heard walking about in midnight. Bhuts are also the lieutenants of the goddess and the black and hairy Khyak and Khyakini are benevolent night spirits who dance in joy and sport, signifying the restoration of peace. The accompanying music is provided by mwali (pipe), pashchima (drum) and chusya jhali (cymbals).

The mask of Mahakali is red with tusk-like teeth, It is also used for Nava Durga dance. Kumari’s mask is also red and that of Mahalakshmi is yellow. The goddesses wear skirts of the same color as their masks. Five lines of black, white, red, yellow and green are stitched to the hem of their skirts. The masks of goddesses are decorated with chhatra (umbrellas), lotus and moon patterns . The masks are made of clay, paper and cloth and are worshipped before a performance. The ornamental headgears of goddesses fixed on frame are attached to a metal or bamboo design framing the face.

The red masked Lakhe, a mischievous local demon runs through the streets during Indra Jatra bestowing blessings and spreading cheer.