In Hinduism, Kamsa (Sanskrit: Kaṁsa), spelt as Kansa, is the tyrant ruler of the Yadava or Vrishni kingdom with its capital at Mathura. He is the brother of Devaki, the mother of the god Krishna - who slew Kamsa. Kamsa is described as human in early sources and an asura (demon) in the Puranas. His royal house was clled Bhoja and his another name was Bhojapati.
Kamsa was born to King Ugrasena and Queen Padmavati. However, out of ambition and upon the advice of his personal confidante, Banasura, Kamsa decided to overthrow his father and install himself as the King of Mathura. Therefore, upon the guidance of another advisor, Chanur, Kamsa decided to marry Asti and Prapti, the daughters of Jarasandha, King of Magadha.
After a heavenly voice prophesied that Devaki's eighth son will slay him, he imprisoned Devaki and her husband Vasudeva and killed all their children; however the eighth son, Krishna, an avatar of the god Vishnu, was transported to Gokul, where he was raised in the care of Nanda, the head of cowherds. Kamsa sent a host of demons to kill the child Krishna, all of whom Krishna killed. Finally, Krishna arrived in Mathura and slew his uncle Kamsa.