Chapter 18 of 42 · Shata Rudra Samhita · Overall chapter 247 of 464
Eleven Avataras
When the gods are routed by daityas, Kashyapa's austerities at Shiva's lingam in Kashi produce eleven simultaneous Rudra-sons through Surabhi and Kashyapa, who turn the tide of the war decisively - the eleven Rudras of later tradition, each commanding a crore of followers and still radiant in the firmament today.
Nandishvara said
Hear of Shankara's eleven supreme avataras; whoever hears of them need fear no obstacle born of falsehood. Earlier all the gods, with Shakra as leader, were beaten by the daityas and fled in terror from their own city, Amaravati. Oppressed by the daityas, they went to Kashyapa, bowed with joined hands, agitated, and affectionately told him everything, their misery from the defeat. Their father Kashyapa, whose mind was fixed on Shiva, heard of the immortals' grief and was deeply unhappy. The sage comforted them and, serene in understanding, held himself steady. Then, very cheerfully, he went to Vishveshvara's city, Kashi, bathed in the Ganga by the rules, worshipped the lord Sarveshvara Vishveshvara together with Uma, properly set up a lingam of Shiva and performed extensive austerities directed to Shambhu, cheerfully, for the gods' welfare. A long time passed. Patient, with his mind fixed on Shiva's lotus feet, he waited, and then, to give the rishi a boon, Shambhu appeared, attached to those devoted to him, friend of the distressed and goal of the virtuous.
Seeing Mahesha, Kashyapa folded his hands and bowed, and, wide in understanding, praised him gladly. He called him lord of the gods, Mahadeva, kind to those who take refuge, Sarveshvara, the supreme self reached through meditation, without decay, the chastiser of the strong, refuge of the good, friend of the distressed and ocean of compassion, whose skilled mind was bent on protecting devotees. The gods were his own and especially his devotees, and had now been defeated by the daityas; he asked him to save those miserable ones, since even Vishnu could not counter this repeated misery. That was why the grieving gods had taken refuge with him and told him. He had completed these austerities faithfully to please him and take refuge in him, and asked Shiva to fulfil his wishes and end the gods' misery. He was himself especially miserable because his sons were suffering, as gods and yakshas were born his sons and were beaten. The daityas were very strong, so let Shiva give the gods joy, help them in every way, and keep the daityas' obstacles from binding them. Hearing him Sarvesha Shankara spoke words of assent, and, while Kashyapa looked on, Bhagavan Hara vanished.
Very glad, Kashyapa quickly returned home and lovingly told the lords among the gods all that had happened. To make his own words true, Shankara Sharva was born through Surabhi and Kashyapa in eleven forms, all full of Shiva, and there were great festivities. The gods came happily to the sage Kashyapa's house to see them. They were Kapalin, Pingala, Bhima, Virupaksha, Vilohita, Shastri, Ajapada, Ahirbudhnya, Shambhu, Chanda and Bhava. These are said to be the eleven Rudras, sons of Surabhi, forms of Shiva born to do the gods' work and ensure happiness. These brave sons of Kashyapa were very strong and valiant, helped the gods in the battle and killed daityas. By the Rudras' favour the gods were fearless and beat the daityas, and Shakra and the others got their kingdoms back and their minds returned to their natural state. Even today all the great Rudras are Shiva's own forms. To protect the gods they always shine in the firmament, live in Ishana's city, are kind to devotees and play in many ways there. A crore Rudras are described as their followers, and, dividing themselves, they live everywhere in the three worlds. Nandi said he had described Shankara's eleven avataras, the Rudras, who bring happiness to all worlds. This unblemished account destroys all sins, gives wealth, fame and long life and grants all that is desired. A person who controls himself and hears it or has it heard enjoys every happiness and afterward gains liberation.
Retold in our own words from Bibek Debroy's English translation of the Shiva Purana (Penguin Classics). Names, numbers and the order of events follow the source.