Kaal Bhairav approached Brahma and utilized his nail to cut his top head. The pinnacle of Brahma, turned entangled in his hand, as represented in the representational depiction of Lord Kaal Bhairav commonplace in all tempLord Kalabhairava can be the lord of Kashi. This has a symbolic importance also. https://www.youtube.com/watch?v=0vLISs2kzMI