From Prajapati, when he had become enfeebled, the deities departed. Only one god, Manyu, did not leave him, but continued extended within him. Prajapati wept. The tears that fell from his eyes remained in that ‘Manyu’. He became Rudra with a hundred heads, a hundred eyes, and a hundred quivers. Then the other drops that fell from him in unnumbered thousands entered into these worlds. They were called Rudra because they sprang from him when he had wept. This Rudra with a thousand heads, eyes, and quivers, stood with his bow strong, and arrows on the string, causing terror, and demanding food. The gods were afraid of him. They said to Prajapati,: ‘We are afraid of this being, lest he destroy us.’ Prajapati said to them: ‘Collect for him food, and with it appease him.’ They collected for him this food, the Satarudriya.
SATAPATHA BRAHMANA, 9.1.1.6-7
kathA 