In ancient times, the forest surrounding Tirumullaivayil was occupied by two notorious tribesmen, Vaanan and Onan from the Kurumbar tribe. King Thondaiman, the then ruler of the land, wanted to put an end to their atrocities. All his attempts went futile and finally he decided to defeat them in war. He set out for the war with all his infantry and cavalry with elephants and chariots. En route to the war, they waded through a dense growth of Mullai plants (Jasmine climbers). The foot of the elephant on which he was mounted was entangled in the dense foliage. The king and his men, in an attempt to free the elephant from this mess, went on to cut the wild twines with their swords and daggers. Suddenly they noticed blood gushing out from the leaves and found a 'lingam' bleeding. Shocked, the King was in great distress that he has committed a sin. Seeking mercy and forgiveness from Lord Shiva, he prayed to Him. Without any delay Lord Shiva and Parvathi appeared before the King lest he indulge in self-inflicted injury out of grief. The Lord asked the King to build a temple for Him right there and promised that he would reside there as 'Masilamaniswara', the Lord who is as precious as a gem, but without stains. It is believed that the Lord also promised to support him in destroying the Kurumbars by sending his holy steed, the Nandi bull. On his orders, the Nandi also gets ready to go and fight for the King. This is why the Nandi in this temple faces outwards, ready to leave for the battle on the orders of the Lord, whereas in all other Shiva temples, it faces inwards facing the Lord.