Kartavirya Arjuna was a legendary king in Hindu mythology. He is also known as Sahasrabahu Arjuna or "Arjuna with a thousand arms" because of a boon he received from the sage Jamadagni, father of Parashurama.

According to the legend, Kartavirya Arjuna ruled over the kingdom of Mahishmati, which was located in central India. He was a powerful and just ruler, who was greatly respected by his subjects. One day, while on a hunting expedition, Kartavirya Arjuna and his army came across the hermitage of Jamadagni. The sage welcomed the king and his army and offered them hospitality. However, when Kartavirya Arjuna saw the sacred cow of the hermitage, he demanded it as a gift.

Jamadagni refused to part with the cow, as it was the source of livelihood for his family. Angered by the sage's refusal, Kartavirya Arjuna and his army attacked the hermitage and killed Jamadagni. When Parashurama, the son of Jamadagni, learned about the killing of his father, he took revenge by killing Kartavirya Arjuna and destroying his entire army.

The story of Kartavirya Arjuna has been recounted in various ancient Hindu texts, including the Ramayana and the Mahabharata. His name is often invoked in Hindu mythology as an example of the consequences of arrogance and disrespect towards sages and saints.