Kali - Mahavidya

Kali stands on Shiva

Kali is one of the Mahavidyas. Krishna avatar of Vishnu is portrayed at the bottom.

Image of Satguru Sivaya Subramuniyaswami
A satguru is needed because the mind is so cunning and the ego is a self-perpetuating mechanism. It is he who inspires, assists, guides and impels the shishya toward the Self of himself.
—Gurudeva