Nagaraja is a Sanskrit word from naga (snake) and raj (king) meaning King of Snakes. It is applied to three main deities, Anantha (Sheshanaag), Takshak, and Vasuki. Anantha, Vasuki and Takshak are brothers, children of Kashyap and Kadru, who are the parents of all snakes. Anantha, the eldest brother, was a devotee of Vishnu, and represents the friendly aspect of snakes, as they save food from rodents. Lord Vishnu is always on continuous meditation (Yoganidra) with Anantha forming a bed for him, and this posture is called AnanthaSayana. Vasuki, the younger one was a devotee of Lord Shiva. Lord Shiva always wears Vasuki around his neck. Takshak represents the dangerous aspect of snakes, as they are feared by all due to their venom.
A temple devoted to Nagaraja exists in Poojappura of Thiruvananthapuram District in Kerala, India. It is known as Poojappura nagarukavu Temple. The uniqueness of this temple is that here the family of the Nagaraja including Nagaramma, Queen of Naga and Nagakanya, Princess of the Naga kingdom is placed inside a single temple.