A King of Thekkumkoor royal dynasty was a big devotee of Thrissur Vadakkumnathan. Though there was a large Shiva temple called Thalikotta Temple near his palace, where he regularly used to visit, he could not be happy without a visit to Vadakkumnathan Temple once in a month. Despite all problems faced, he used to visit Vadakkumnathan Temple throughout his life. But, as years passed, the King became aged, and he could no longer travel for long distance. Thus he was sunk in grief. Lord Shiva appeared before him and consoled him saying that he would appear in a location where his great devotee can travel easily. Thus the King was pleased.
During his return, the King also visited the famous Shiva temple at Vaikom. There he met with a poor Brahmin, named Perepparambu Namboothiri, who was conducting his bhajanam due to financial difficulties. The King told him that he would provide all necessities for getting money, and took him to his palace. That night, the King had a dream, in which
Lord Shiva appeared before him, and saying that he would appear in Nakkarakkunnu - a small hill located a few miles away from the palace area - as a Swayambhoo lingam, and there would be an idol of Nandi, his vehicle in front of him, and a white ixora plant on his backside towards the left. The King became very much happy.
Nakkarakkunnu, the place where the present temple exists, was a huge forest area then. Wild animals roamed there without any problem. No one wanted to settle there, even if it was given freely. There was a monastery called Swamiyar Madom, titled Thrikkaikkattu Madom, on the north-east side of the temple. On the day after the King got the darshan of Lord Shiva, two servants from the Swamiyar Madom - Changazhissery Moothathu and Punnassery Moothathu - went to collect wood and fire for a homam (fire ritual).
They saw a stone there and scraped their sickle on it, but suddenly it started bleeding. They soon realised that it was a Swayambhoo Shivalingam. The news spread like a bush fire, and it also reached the ears of the King, who could not control his emotions after hearing the news. The King came to the location where the lingam was installed, and prostrated before it. He also found that there was an idol of Nandi in front of it, and a white ixora plant on its backside towards the left. After that, he made the biggest temple in his territory for his favourite deity, with all the major components of a mahakshetra (major temple). Tharananelloor Nammbothiri became the head priest of the temple, and Perepparambu Namboothiri was installed as the senior priest. The King got blessed by visiting the temple, and lived his life happily thereafter.
Brahmarakshas : There is an interesting story behind the Brahma Rakshas. One person called Moose was a great friend of the king. The king was not known for his beauty but his friend Moose was very handsome. The queen fell in love with this friend knowing which the king ordered his servants to kill Moose. Instead of killing him, the King’s servants killed the junior priest of the temple (keezh santhi). The wife of the priest became a Brahma Rakshas and started seeking revenge. So the king built a temple for her. For a long time afterwards, women do not prefer to enter this temple.