Karthaveeryarjuna is a legendary king mentioned in the Ramayana, Mahabharata and Vayu purana. He is considered as the incarnation of Lord Sudarshana ( the chakra of Lord Vishnu) and was one of the disciples of Lord Dattatreya. He dhyana sloka talks of him having thousand hands.
Karthaveeryarjuna Homam is performed to find lost or stolen things, lost people. It is performed by chanting the Karthaveeryarjuna mantra and offering oblations into the sacrificial fire (agni).