The temple is related to Ashlasha-Ayilyam star.  Those born of Ayilyam star are generally short tempered and active and also dull at times.  They are fair in complexion with broad eyes.  They will teach righteousness to others.  They are fond of earning and ornaments.  They are spendthrifts too. The Vinayaka of the temple is praised as Karkadaga Vinayaka.  There are shrines for Lord Muruga with Valli and Deivanai and Lord Nataraja in the corridor.  Navagrahas the 9 planets have no place in the temple. The name Tirunthudevankudi relates to the story of Indira worshipping in the temple and correcting his mistake.  Devan is Indira.  Tirunthu means correcting oneself.  Local people do not know this name.  They know the temple only as Nandukoil.

Ayilam starrers worship in this temple for relief from adverse planetary effects, performing abishek to Lord Karkadeswarar with gingely oil.  It is believed that consuming this abishek oil heals illnesses.

Those belonging to Ayilya star are advised to pray in this temple as often as they could or on their star days or on their birth days. It is said that the Swaymbulinga in the place was buried under the sand due to heavy floods during the reign of a Chola king who was attacked with paralysis.  No treatment yielded results.  He was praying to Lord Shiva for remedy.  An aged couple practicing medicine came to his court and offered him the sacred ash with water.  Surprisingly, the king was cured instantly and stood up majestically.  He begged the old couple to stay with him as doctors of the royal family in the palace but they refused.  He offered them gold and other gifts which too they declined to accept.  The king promised them that he would give them anything they wished.  They brought the king to this spot and asked them to build a temple for Lord Shiva. They merged in the Shivalinga there.

Realizing that the couples were none other than Lord Shiva and Mother Parvathi, the king built the temple at the place.  Worshipping Shiva here ensures all cures from any illness.  Saivite saint Tirugnanasambandar had mentioned the Lord as Healer in his hymns.

There are two Ambicas in the temple.  When the king built the temple, he could not get the original Ambica idol.  He made a new one and installed it as Arumarundhu Nayaki – Goddess of rare medicine.  Within a few days, the original idol also appeared.  Installing that too, he named her Apoorva Nayaki who is the principal Goddess of the temple.

Yoga Chandran: This is the temple for remedies needed for Punarvasu (Punarpoosam), Pushya (Poosam) and Ayilayam (Aslesha) starrers falling under Cancer square in the zodiac.  We can see a hole on the Linga made by a cancer (nandu) and an injury scar caused by Indira.  Planet Moon is in a shrine at the entrance of the temple in meditating form as Yoga Chandra.  Those undergoing Moon main period in their life are advised to offer white vastras (clothes) to Chandra if they have adverse aspects.

Aslesha-Ayila star under Karkadaga-Cancer Rasi has naturally medicinal powers.  They also have the confidence that they achieve through divine backing.  They have a firm mind.  They should pray to Lord of this temple on their star days, new moon days, Tuesdays, Saturdays and on Ashtami days in the new moon fortnight.  People of other stars too may depend on Lord Karkadeswara and Arumarundu Nayaki for cure from prolonged diseases.

Sage Durvasa was mocked at by a Gandharva (a community known for their skill in music) that he was walking like a cancer-nandu.  The sage was just completing his Shiva Puja.  The angry sage cursed him to become a Nandu.  When he begged for pardon, the sage advised him to worship Shiva for relief.  He followed the advice and got relieved.  As the Lord graced the Nandu-Karkadaka- He is called Karkadeswarar.

Indira the king of Devas, following the advice of his Guru Prahaspati worshipped the Lord here with 1008 flowers daily after a dip in Pushkarini and corrected himself for the wrongs he committed.  Tirundhu means correcting oneself.  Devan is Indira.  Hence the name of the place is Tirundhu Devan Kudi.   Locals know the place only as Nandu Koil.