The Supreme Serpent Master, also known simply as the Supreme Master, was the ruler of the Serpent Masters on Ophideraan. In 0 ABY, the position was held by Tyrann.
The Supreme Master ruled the Serpent Masters and their slaves from the upper levels of the Great Well. He wore a medallion around his neck that contained a transmitter used to control the Ophideraan flying serpents. This was ultimately destroyed by Luke Skywalker, and the Serpent Masters were overthrown by the slaves.