Karavīra-pura was the capital city of the Padmāvata country. Padmavarṇa, the second son of Yadu, founded it on the bank of the Veṇā river, on the Sahya mountain. Later it was ruled by Śṛgāla, a kinsman of the Yādavas. Śṛgāla became a cruel ruler, and Bhagavān Kṛshṇa slew him with the Sudarśana cakra during the campaigns around Gomanta Parvata.

Foundation

Padmavarṇa was the second son of Yadu, from the Nāga-kanyā line. Yadu told him to settle on the Sahya mountain in the south. Padmavarṇa built his city on the bank of the Veṇā river. It looked as if Viśvakarman himself had built it. The land around the city was called Padmāvata. (Harivaṃśa, Vishṇu Parva, Chapter 39)

Paraśurāma’s warning about Śṛgāla

Paraśurāma met Bhagavān Kṛshṇa and Balarāma at the Veṇā river and advised them on their way to Gomanta Parvata. He warned them in particular about Karavīra-pura. He said: “Your kinsman Śṛgāla, son of Vasudeva, rules this city. He is wrathful, drunk with pride, has slain many kings, and even hates his own sons. Do not stay there.”

Even so, Kṛshṇa and Balarāma passed through that region after the battle at Gomanta, and the meeting with Śṛgāla followed. (Harivaṃśa, Vishṇu Parva, Chapter 40)

The Śṛgāla episode

After the battle at Gomanta Parvata, Kṛshṇa and Balarāma travelled to Karavīra-pura. Damaghosha, king of Cedi, went with them. Śṛgāla, the ruler of the city, came out in his chariot of the sun, a gift from Bhagavān Sūrya that he had won through worship. He challenged Kṛshṇa to single combat.

Bhagavān Kṛshṇa slew Śṛgāla with the Sudarśana cakra. Then, out of compassion, he crowned Śṛgāla’s young son Śakradeva as king of Karavīra-pura. In this way he kept the rightful line on the throne and left the city in peace. (Harivaṃśa, Vishṇu Parva, Chapter 45)

Sources

Harivaṃśa Purāṇa, Vishṇu Parva, Chapters 39–40, 44–45