Emperuman has manifested in the form of Anandan (popularly known as Adhiseshan, the five headed snake) in this temple. He is present in a seperate sannidhi next to Ulagalandha perumal in Thiru Ooragam. Ooragam signifies snake and lord Vishnu gave dharshan to Mahabali as the serpent lord, this place came to be called Ooragam and the lord is called Ooragathan.
One popular belief is that this lord fulfils prayers of unwedded girls for early marriage. A framed picture of this lord can be found on the inner prakaram of Perundevi thaayaar (thaayaar sannidhi in Varadarajar temple - Kanchipuram), the picture is identified as ‘Kalyana Naagar’. You can notice devotees tracing the profile of the lord with manjal (turmeric) prasadam.
This temple is regarded by some as Srivaishnava Navagrahasthalam for Raghu, and the lord blesses childless couples.