Question: how krishna got sudarshan chakra?
Answer: According to the Mahabharata, Krishna and Arjuna were asked by the fire god Agni to help him resist Indra; and since they had no weapons, he gave Arjuna the bow called Gandiva, and to Krishna he gave the Sudarshana Chakra, the disk with 108 serrated edges that belonged to Vishnu (whose avatar Krishna was).