Tamar was a Teplan male who lived during the mid-24th century. He suffered from the Blight, introduced to his world by the Dominion through the Jem'Hadar.
In 2372, Teplan volunteered to help Dr. Julian Bashir in hopes of finding a cure for the disease. Dr. Bashir was unable to find a cure for those like Tamar who had entered into the "quickening", or end stage of the disease. He died that year.
Because of those like Tamar, Bashir was able to find a vaccine that would inoculate the fetuses of pregnant women against the disease. Though his generation would die, the next generation would survive, and the Blight would end. (DS9: "The Quickening")
Tamar was played by actor Alan Echeverria.