Muchukunda was a king ruling over South India having his capital at Karur. Desirous of doing tapas on Lord Subrahmanya, the king approached sage Vasishtha and requested him for initiation into the correct observances of the Vratas. The sage explained to the king the importance of observing the Sukravara (Friday), Karthikai, and the Kanthar Sashti Vratas of Lord Subrahmanya.
Having learnt in detail the Vratas, their importance and the methods of observing them, King Muchukunda started observing them with faith and devotion. After sometime, while the king was greatly absorbed in his devotion to Lord Skanda, the Lord appeared before him and granted him many boons. The Lord had made his followers, Virabahu and other warriors of his own forces, serve the king. At the behest of the Lord, Virabahu Devar and others, taking human births, obeyed the commands of the King and helped him. The king enjoyed much peace, plenty, and prosperity by Lord Skanda’s grace.
King Muchukunda’s might was such that even Devendra had to approach him to get his help for defeating the Asuras. The king complied with the request of Indra and defeated the Asura King Valan. When he returned from Devaloka, Kung Muchukunda was given by Vishnu the murthi (idol) of Somaskanda. Arriving at his kingdom, the king performed the Pratishtha Ceremony for the Somaskanda Murthi at Thiruvaarur, in South India. After sometime he had a son, Agnivarman by name. Entrusting the kingdom to his son, the king retired peacefully to Mount Kailasa for spending the rest of his life in Tapas.
Sivananda, Swami. Lord Shanmukha and His Worship. World Wide Web edition. India: Divine Life Society, 2000.