Nagas in Sanskrit means snakes. It is given by the vedic aryan for Nagas people worship snake. Kiratas on the other worship phallus stone. After the arrival of vedic aryan, these 2 culture of worshiping stone and snakes were taken in by the vedic culture. Today in Hinduism, phallus stone (Shiva Lingam) is adorned with snakes around it , representing Shiva with snake around his neck. Naag Devata is also is also a protector of many deity's such as the Bed of Shri Vishnu the Garland of Lord Shiva and Umbrella of Mariamman, The one who clears the path of Kaala Bhairava and Shri Ganesh Ji's belt.