In the Vedas there is a proto-Kali, a goddess of death, destruction, bad luck and grief. Called Nirrti, this awesome power was black in complexion, wore black clothes and rather incongruously had long golden hair. The only black skinned blonde goddess in all mythology I think. She lived in the South, the direction of death. While she was not Kali, she shares this trait with her in being unambiguously associated with and causing death. The presence of Nirrti in the official canon helped quite a lot when Kali had to be engaged with, by the guardians of the faith. So similar are the two indeed that Nirrti has vanished from the popular imagination, Kali being more than adequate to fulfill all her roles.

For about two thousand years after that we have textual silence on Kali. The first mention of her is in the Mahabharatha and the accounts given vary widely. She seems to be a minor personage in Heaven, or one of the two warrior goddesses, Kalika and Bhadrakali, who accompanied Skanda (one of the foremost culture heroes of India) into battle. Yet a vital point about them is made here which will become the norm about all future descriptions of Kali. They live in trees, mountains and hills, crossroads, jungles, caves and cremation grounds. The two goddesses speak many tongues, i.e. not the language of the elite like all other well behaved gods.