Some time ago Swami Vishwananda "installed" a big stone in front of the Kali Temple. I asked him about the meaning and he told me:
"It is Bhairav, a guardian who takes care for the Devis. He came into my dream one night and told me where I would find this special stone in the forest. I send somebody to the place and he found the stone."
Now here is the story of Bhairav:
The young Vaishnava Devi goddess went ahead and Bhairav (a selfish Demon) followed her. She kept a guard outside the cave and asked him not to allow Bhairav to enter the cave. When Bhairav tried to enter the guard forbade him and a terrific battle started. There after Devi took the form of goddess Kali and killed Bhairav. In the dying moment Bhairav said: "Mother, I am not mourning my death as I have died at the hands of mother creator. But I pray you gracious mother to pardon me. I did not know you in the girl form. Mother, if you do not forgive my sins then the whole world may hate me." On hearing the cry of a child addressed to the mother again and again, mother took pity on Bhairav and gave him a boon of liberation. She not only granted Bhairav liberation from the cycle of reincarnation, she said also: “My devotees will always visit your place after having my 'Darshan'!”
So it came that it is believed that the Prayer to the Devis is only complete after worshipping also Bhairav.