Why Parashurama toured the world 21 times and killed many kshatriyas?
There was a king names Karthaveeryarjuna, King of Mahishmati, son of Krutaveerya who was a strong devotee of Sri Dattatreya and blessed with his invincibility. He possessed the strength of a thousand arms on the battlefront. He had defeated Raavana at war and was reigning at Mahishmati, full of glory and arrogance. Once King Karthaveeryarjuna went on hunting and was tired, thirsty and hungry and came to the Jamadagni Rushi’s ashrama. The sage Jamadagni arranged the entire troup of Karthaveeryarjuna, with a royal feast and felt very happy. The king enquired the sage as to how come you have prepared such a delicious food within a short period of time. Then the sage told him that he has Cow called Kamadhenu which can give anything we require and because of that only that he could give such a good food so quick. Karthaveeryarjuna demanded the cow, but the sage refused to give the Kamadhenu. Then the king ordered his solders to take away the cow by force. By that time, Parashurama who had g