Ayyappan is his real name.
Talk about it here.
Ayyappan, later renamed Narayan after suffering from amnesia, was the head of Mythology and Folklore at Calcutta University in 1926. He was originally from Karabar Caves, where he was found with his memories lost. When he arrived back at the caves with Nyssa, he remembered his true heritage and his true name Ayyappan. He died helping his sister Dawon to fight Shardul Khan for control. (AUDIO: The Emerald Tiger)