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|Kamsa or Kansa|
Vasudeva and Devaki traveling in a carriage
|Place of death||Mathura|
|Consort||two daughters of Jarasandha|
|Dynasty||Surasena or Yadu|
In Hinduism, Kamsa or Kansa (Sanskrit: कंस), often known as Kans in Hindi, is the brother of Devaki, and ruler of the Vrishni kingdom with its capital at Mathura. His father was King Ugrasena and mother was Queen Padmavati. However, out of ambition and upon the advise 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 the two daughters of Jarasandha, King of Magadha, who was, in turn, a friend of Banasura. Their names were Asti and Prapti.
In reality, Kamsa was not the biological son of Ugrasena. In the Bhagavata Purana it is revealed that, once Kubera's servant, a Gandharva called Gobhin was flying over the city of Mathura and upon viewing Padmavati's irresistible beauty, he took the form of Ugrasena and seduced her, resulting in the birth of Kamsa. In fact kamsa in his previous birth was a demon called Kalanemi,who was slain by Lord Vishnu.
Annexation of Kingdom 
During his wedding in Mathura, Jarasandha brought over his army to escort the Princesses Asti and Prapti. Using the army of Magadha as his political cover, Kamsa overthrew his father after he refused to voluntarily retire from his position. This was done within the confines of the royal palace and the public was not informed. After Ugrasena failed to show up for public events, Kamsa announced his coronation.
Kamsa was told in a prophecy that the eighth child of Devaki would kill him. A loving brother, he didn't want to kill Devaki, and so instead imprisoned both Devaki and her husband, Vasudeva. In the confines of the prison, Devaki repeatedly conceived, and an enraged Kamsa murdered the first six children. The seventh child, Balarama, was saved when he was moved to Rohini's womb. The eighth child born to Devaki and Vasudeva was Krishna. Krishna was saved from Kamsa's wrath and raised by a cowherd couple, Nanda and Yasoda.
After Krishna grew up and returned to the kingdom, Kamsa was eventually killed by Krishna, as was originally predicted by the divine prophecy, and Ugrasena reinstated as King of Mathura.
Other Mentions 
Kanishka or Kanisha or Kamsa In his documentary "The Story of India", (A BBC Production) Michael Woods tried to show a link between Kamsa and Kanishka. Kanishka was a ruler who ruled with Mathura as its capital. Although this is quite controversial and ungrounded. Mahabharata even though exists as a legend is nowhere near the period of Kanishka. Kanishka was a Buddhist and according to Hinduism, Buddha was born after Krishna.
- Dictionary of Hindu Lore and Legend (ISBN 0-500-51088-1) by Anna Dhallapiccola