Shree Kalbhairav is the most important amongst the eight Bhairavas. He is the overseer of time, the protector of travellers, the Kotwal of Kashinagari, the destroyer of sins, and the protector of the Worlds.In the Skand Puran, Shree Kartikeya tells Maharishi Agastya, the Divine Legend of Shree Kalbhairav.

Once, there raged a celestial war between Shree Brahma and Shree Narayana, both had claimed to be the “One invisible power that Lords over the 3 worlds”. As the outcome was not forthcoming they asked the four Vedas to resolve the debate. To their shock and dismay, the Vedas named Lord Shiva, as the Paratatwa. Lord Shiva appeared before them. Out of rage and pride, Lord Brahma insulted Lord Shiva, “O Sankara, You are born from my own forehead. Take refuge in me, I will protect you.”

Angered, Lord Shiva created Shree Kalbhairav, “O My son, You are as potent as Kala (Yama). Hence You are the very Ruler of Time. Punish Lord Brahma, by cutting off one of his heads, for his pride. To atone for your
Brahma-hatya, you will have to roam the world as a medicant, with Lord Brahma’s skull stuck to your palm as a medicant bowl. After your wanderings, go to Kashi, the city of deliverance, where your sin will be wiped off and the skull will fall from your palm”. As promised, in the Shrine of Kashi, Lord Kalbhairav’s sin of Brahma-hatya, was wiped off. The skull fell from his palm, and there he continues to dwell, protecting the people of Kashi, destroying the sins of his devotees. Such is the tale of Shree Kalbhairav in the 13th canto of Kashi Khanda of the Shree Skanda-Purana.