नीलकण्ठमीप्सितार्थदायकं त्रिलोचनम् । Lord Shiva has various varieties and avatars (manifestation of the deity in physical body form). Although his primary ascetic type is greatly revered, his  Guru and ācārya informs which mantra to employ for Bhairava sadhana, what bhaav or feelings a single ought to be in for Bhairava https://webtagdirectory.com/listings13053387/kaal-bhairav-secrets