Ilamthuruthy Maha Vishnu Temple is a subsidiary of the Thirumallapalli Mahadevakshetram. The presiding deity here is Maha Vishnu, who incarnated as Narasimha to vanquish the tyrannical king Hiranyakashipu, father of the devout Prahlada. Unlike the fierce aspect of Narasimha, the deity is represented here in a calm and benevolent form, symbolizing Vishnu's readiness to grant blessings to devotees, particularly Prahlada. It is believed that all who seek his blessings at this temple will have their wishes fulfilled.