A prophecy, and what it cost first
At Devakī's wedding to Vasudeva, a voice prophesies that her eighth child will kill her brother Kaṃsa. Kaṃsa, king of Mathurā, responds by imprisoning his own father Ugrasena to seize the throne outright, then imprisoning Devakī and Vasudeva and killing six of their infant children as each is born, trying to prevent the prophecy by eliminating every candidate for it in advance.
Raised elsewhere, summoned back
The eighth child, Kṛṣṇa, is secretly carried to Vraja and raised among the cowherds, beyond Kaṃsa's direct reach, while Kaṃsa continues sending assassins after him across his childhood. Grown, Kṛṣṇa and Balarāma are eventually invited back to Mathurā by Kaṃsa himself, under the pretext of a wrestling festival — a trap, staffed with wrestlers (Cāṇūra and Muṣṭika) specifically tasked with killing them in the arena.
The arena
Bhāgavata Purāṇa Canto 10, Chapter 44 ("The Killing of Kaṃsa" in the Vedabase English edition) records the outcome: Kṛṣṇa kills Cāṇūra, Balarāma kills Muṣṭika, and Kṛṣṇa then goes directly to Kaṃsa's own raised seat, drags him down by the hair, and kills him in front of the full assembled court of Mathurā — the killing is public, direct, and performed by Kṛṣṇa's own hand rather than delegated or disguised.
After the killing
Having killed Kaṃsa, Kṛṣṇa frees his grandfather Ugrasena from imprisonment and restores him to the throne of Mathurā, rather than taking the kingship for himself. The text records no claim by Kṛṣṇa to Kaṃsa's throne or his wealth — the stated resolution is the restoration of the king Kaṃsa had deposed, not a transfer of power to the one who killed him.
Sources
- Bhāgavata Purāṇa, Canto 10, Chapters 36–44. The wrestling-festival invitation and preparations (36 onward) through the killing of Kaṃsa and the restoration of Ugrasena (44). Chapter 44 is titled "The Killing of Kaṃsa" in the Vedabase English edition.
- Note on a discrepancy. Chapter numbering for this episode varies between editions — Prabhupāda's Kṛṣṇa Book numbers the same episode as Chapter 43 rather than 44. This essay follows the Vedabase/Bhāgavata canto-chapter numbering and flags the variance rather than silently picking one.