Introduction
Ahirbudhnya, "the serpent of the deep", is one of the eleven Rudras, a group of deities who are aspects or manifestations of Shiva in the Puranic tradition.
The eleven Rudras (Ekadasha Rudras) are a group of deities who are aspects or manifestations of Shiva. The idea goes back to the Vedic Rudra and the Maruts, who are sometimes called the sons of Rudra. The Brihadaranyaka Upanishad (3.9.4) says that the eleven Rudras are the ten vital breaths and the mind, and are called Rudras because when they leave the body at death, they make people weep (the verb rud, "to weep"). In the Puranas, the eleven Rudras are sons of Kashyapa and Surabhi, or of Kashyapa and Aditi, or manifestations of Shiva. The lists of the eleven names differ between the Mahabharata, the Harivamsha and the Puranas. This article follows one Puranic list: Ajaikapada, Ahirbudhnya, Pinakin, Ritadhvaja, Tryambaka, Maheshvara, Vrishakapi, Shambhu, Hara, Ishvara and Kapardin.
The Rudras are worshipped together in the Ekadasha Rudra rites, in which the Rudram hymn is recited eleven times over an abhisheka of Shiva. A tradition regards Hanuman as the eleventh Rudra, an incarnation of Shiva.
Name and early references
Ahirbudhnya is an old Vedic deity, whose name means "the serpent (or dragon) of the depths", and who is associated with the deep waters of the atmosphere, often in a pair with Aja Ekapad. He is invoked in the Rigveda in the group of gods called Vishvedevas.
In the Puranic tradition
He is the deity of the nakshatra Uttara Bhadrapada. A Pancharatra Vaishnava text, the Ahirbudhnya Samhita, is named after him, and in it Ahirbudhnya is the narrator of teachings, showing how the name was taken into another tradition. In the Puranic lists, he is one of the eleven Rudras.