Vasuki is a nagaraja, one of the King serpents of Hindu mythology and Buddhist mythology. He is a king of the nagas and has a gem called Nagamani on his head. Manasa, another naga, is his sister. Vasuki is Shivas snake. He is known in Chinese and Japanese mythology as being one of the eight Great Dragon Kings (八大龍王 Bādà lóngwáng), amongst Nanda (Nagaraja), Upananda, Sagara (Shakara), Takshaka, Balavan, Anavatapta and Utpala.
Bio from Wikipedia - See more on en.wikipedia.org Text under CC-BY-SA license