This depiction of Kali and Shiva references the human experience of death. Kali, who represents dissolution mates with Shiva, who represents creation. She drives him mad and he forgets who he is. For a time, Shiva is lost. Such is death.
Keshava is a name of Vishnu from within Hindu tradition. The name appears as the and names in the Vishnu sahasranama of Mahabharata. Lord Keshava is venerated by those persons wanting to avert bad luck, or ill omens.