Cheranalloor Kartha Family of South Chittor was the founder of Ernakulam Siva Temple.As per the devaprasna this temple have a connection with Vaishnava.Jadavedan nampoothiri was the swamiyar of Ernakulam Siva Temple and Thiruvananthapuram Shri Padmanabhaswamy Temple.He was a member of Cheranalloor Kartha Family of South Chittoor
The temple's legend is deeply associated with Hindu epic Mahabharata. Arjuna, the 3rd Pandava made a severe penance to propitiate Lord Shiva. Pleased with Arjuna’s devotion Shiva accompanied with his consort Sri Parvathi set out from their abode at Mount Kailash to meet Arjuna.
Shiva intends to impress Parvathi with the devotion Arjuna has towards him. Shiva disguises himself as "Kiratha" a tribal hunter before appearing before Arjuna.Just as Shiva appears before Arjuna he sees a wild boar charging towards Arjuna and shoots an arrow at the boar. Arjuna, who is an accomplished archer, also shoots an arrow at the boar. The boar who was in fact a demon named Mookasura in disguise is killed and its original form is revealed. However, dispute arises between Arjuna and Kiratha as to who is the real killer of the animal. A battle ensues between the two, lasting a long time, ultimately resulting in Kiratha’s victory over Arjuna.
The vanquished Arjuna, unable to even stand up makes a Shiva Linga out of mud and performs a pooja offering flowers. To his surprise, he sees that the flower he offers over the Shiva Linga is falling over the head of Kiratha. Arjuna then realises that Kiratha is none other than his Lord Shiva. Pleased with his devotion and sincerity, Lord Shiva granted Pashupatha Arrow to Arjuna. Arjuna left this place and soon this area was covered with dense forest, uninhabited for long time. The existence of the Shiva linga made by Arjuna also disappeared from memories of all.
Centuries later, a boy named Devala who has been cursed by a sage, now has a body of a snake, crawled into this forest and saw this lingam completely submerged into mud . He worshiped this lingam as part a deep penance in hope for redeeming from the curse. Soon a few people spotted this mysterious man with body of snake and called him as Rishi Nagam (Saint Serpent) and feared even to come near to him. Some even tried to thwart him with sticks etc. Unmoved by all these action, Rishi Nagam continued his severe penance. Finally Lord Shiva and Parvathi appeared in their original form and asked the sage to take a dip in the nearby pond. As soon as he immersed, he was redeemed from the curse. Soon a new idol appeared just near to the original lingam. Based on this legend, the place got its new name, Rishnagakulam (The pond of Rishi Nagam) and the temple was constructed by the public.