Yerdrin Lek in 2165
Yerdrin Lek was an Yridian information dealer during the 22nd century.
In the alternate timeline where the Xindi destroyed Earth, Yerdrin Lek was hired by the Xindi to help find the last colony of humans. They paid him to follow Doctor Phlox when he left Denobula, which he did in 2165 to treat Jonathan Archer. Koss tailed Phlox to the Ceti Alpha system, and informed the Xindi of its location. Though he was captured by Enterprise (where he tried to pose as a dealer in Rigelian flame gems), it was too late. Following his signal, the Xindi attacked Ceti Alpha. Koss presumably died in Enterprise's brig when the ship was destroyed in a subspace implosion. (ENT: "Twilight")
Background
Yerdrin Lek was played by actor Brett Rickaby. The final draft script for "Twilight" dated 11/06/2003 gave this character the name of Yerdrin Lek. Earlier drafts called him "Yedrin Koss", but this was changed because there were already two Star Trek characters with similar names: Dax host Yedrin Dax and T'Pol's husband Koss. Promotional materials for the episode used the earlier, incorrect name, which became widely accepted. It is worth noting the character's name was never mentioned in the episode as aired.