Ottasekharamangalam Mahadeva temple is located at Ottasekharamangalam on the Kattakada – Chembur – Vellara road in Thiruvananthapuram district, Kerala. The annual festival begins on Chathayam nakshatra in Dhanu Masam and ends on Thiruvathira Nakshatra.
The three karas of the region brings three flag posts and the flags are installed in there of them by the Tantri of the temple.
There are two temples dedicated to Shiva and one Vishnu in the shrine. All the three deities are the main murtis in the temple.
In the center is Shiva as fierce Aghora murti. This murti was consecrated by Khara Maharishi. This Shiva was so fierce that it was impossible to perform pujas or enter the shrine. To lessen the ferocity of the Aghora Shiva another Shiva shrine was built known as Thekkedam temple. Some strength of Aghora Shiva was transferred into the new Shiva temple.