Grathon Tolar was a male humanoid alien individual who lived in the 24th century. He had blue skin and a fin-like structure running along the top of his head. He encountered Elim Garak prior to the mid-2370s.
In 2374, Tolar was in a Klingon prison awaiting execution. He was freed by Gowron on Benjamin Sisko's request and traveled to Deep Space 9. While there, Sisko and Elim Garak had Tolar forge a holographic program of a Dominion meeting where Weyoun and Damar discussed the invasion of the Romulan Star Empire. Sisko was forced to bribe Quark after Tolar got drunk at Quark's, attacked M'Pella and stabbed Quark himself. Tolar's holoprogram did not fool Senator Vreenak, although after the Tal Shiar recovered it, the imperfections were attributed to the explosion. Tolar himself was later killed by Garak. (DS9 episode: "In the Pale Moonlight")
Enderby of Starfleet Intelligence later learned of Tolar's involvement in the affair and his murder by Garak. Enderby and Jedburgh would force Garak into attempting an assassination of Tomas Roeder by threatening to reveal his involvement.
Sisko informed William Ross and Marta Batanides of Tolar and his murder by Garak. He would also tell his old commanding officer, James Leyton, as a way of easing his conscience. (DS9 novel: Hollow Men)