The custom of these guhya or secretive Bhairava can be an oral tradition that is continuing in the Expert disciple tradition. Their karmakand rituals and techniques are solution, they're not composed down but only learnt and practiced in guru disciple custom. The Rigveda explained Rudra as being the entity in https://selfbizdirectory.com/listings588544/5-essential-elements-for-kaal-bhairav