From Periyavhachan Pillai Sanctum, travel straight and on the left side, there is a staircase leading to Mettazhagiya Singar Sanctum.
This Mettazhagiya Singar Utsava Moorti was brought from KattazhagiyaSingar Temple, which is about 1.3 km from Sri Ranganatha Swami Temple, and kept in Sri Ranganatha Swami Temple centuries ago, when there was very little human life and this KaattuAzhagiya Singar temple is located in the middle of the forest.
Even today when we visit Kattazhagiyasingar Temple, we can find that the Moolavar or the main deity of Kattazhagiyasingar is in a seated position and that the entire temple is amidst a forest.
You can King Prahlad (ardent devotee of Lord Vishnu) as a child, standing next to Mettazhagiya Singar Perumal, and worshipping him with folded hands.
This Mettazhagiya Singar is also known as Ugra Narasimha Moorti.
Opposite to this Sanctum, there is Kambar Mandapam, which is the place where poet Kambar had staged his Kamba Ramayanam for the first time and got it approved by Lord Mettazhagiya singar .
One can find various paintings of Lord Narasimha on the walls, while entering the sanctum.
There is also a small board with the description of Kambar's Hiranyavadhapadalam (A section from Kamba Ramayanam, which speaks about the incarnation of Lord Narasimha on this earth for his dear devotee Prahlad)