Kali is usually considered to be an aspect of Parvati, the wife
of Shiva. (Parvati is also sometimes known as Uma.) Another aspect
of Parvati is Durga, the ten-armed demon-slaying goddess celebrated
in September-October during Durga Puja,
the largest religious festival in Bengal.
Ma Kali, as devotees affectionately call her ("Mother Kali") is
known to take on many different forms or moods, some related to
particular places, miracles, or incidents (comparable to the many
manifestations of the Blessed Virgin Mary: Our Lady of Sorrows,
Our Lady of the Springs, Our Lady of Perpetual Help, Our Lady of
Lourdes, etc.). Kali's forms range from the benign protectress to
the terrifying demon-slayer. Even robbers who waited in the forests
of Bengal to ambush travelers used to worship their very own form
of Kali: Dakait Kali.
In spite of the variety of forms She takes, Kali can always be recognized
by certain characteristics. Her long hair flies about wildly (unlike
the meticulously plaited hair of a modest Hindu woman), indicating
Her infinite freedom. She is usually depicted standing on the prone
body of Shiva, with Her tongue out. In contrast to Shiva's pure
white complexion (He is smeared with ashes in the tradition of a
Kali is the deep black of a limitless Void that has the power to
swallow up everything. Her name comes from the Sanskrit word kala,
"time"; she is the power of time, which devours all.