Tamar was a male inhabitant of Beta III in the 23rd century.
In 2267, the USS Enterprise landing party met him at Reger's house, when they retreated there to escape the mayhem of the Festival. A grandfatherly figure, Tamar attempted to calm the irascible Hacom, who felt the strangers belonged in the Festival. His gentle comment suggesting that the lawgivers were all-knowing was taken for mockery by Hacom, who became further enraged, and fled the house. Later, Hacom returned with lawgivers, to whom he had reported the conversation. They evidently took Hacom's accusations seriously, for they murdered Tamar. The landing party later learned from Reger that he was part of an underground that was organized in threes, and that Tamar was his contact. With Tamar's death, Reger was isolated from the third man in his cell. (TOS: "The Return of the Archons")