Krishna was a lovable, divine character  from whose flute came divine music and one who was the darling of Brindavan. His uncle, Kamsa, tried his best to kill him as Kamsa was destined to get killed by this divine being. Thus, Kamsa sent Poothani, Shakatasura and Trinavartha in various guises but each one was killed by the young Krishna. Even after Krishna located to Brindavan, Kamsa hounded him in various ways but turned out to be unsuccessful. Together with Balarama, Krishna got rid of  many demons  who haunted a palmgrove. He brought all the Gopas back to life after they drank water filled with Kaliya's poison. Kaliya's end came dramatically after Krishna had a mighty duel with him at the end of which Kaliya left the Yamuna for good. Krishna once brought Devendra to his feet by asking all in Brindavan to worship nature and not Devendra as was the practice.  So, when Devendra let his wrath loose by causing torrential rains, Krishna lifted the Goverdhan hill and provided protection  to every being and creature. Later, he killed the mighty elephant, Kuvalayapeeda, and tore apart  Chaanura in a wrestling match with Balarama finishing off Mushtika. Finally he took on Kamsa whom he killed, then released Vasudeva and Devaki from prison. He married Rukmini, and won the hand of Satyabhama. He saved Draupadi's honour and in the war at Kurukshetra, he became Arjuna's charioteer and advised him on dharma, etc. This came to be known as the Bhagwad Gita. In all his efforts , his only intention was to establish dharma.