Bhairava is also known as on as protector, as he guards the eight directions on the universe. In Shiva temples, in the event the temple is shut, the keys are placed right before Bhairava. आग्नेयां च रुरुः पातु दक्षिणे चण्ड भैरवः ॥ इति श्री काल भैरव ब्रह्म कवच प्राकीर्थितम https://www.youtube.com/watch?v=lqYJ072UzdE