Verjyl Gard was a male joined Trill in the late 23rd and early 24th centuries. As an initiate, Verjyl Slest had gone through an impressively complicated screening process, given the special responsibilities taken on by the Gard symbiont over the previous centuries.

In 2285, Gard was approached by Kov, an agent of the Trill Symbiosis Commission, to track down a suspected joined murderer. He eventually identified the killer as Joran Dax, and was successful in preventing his fourth killing. (DS9 - The Lives of Dax short story: "Allegro Ouroboros in D Minor")

Circa 2356, Verjyl Gard, by then officially retired, was approached by Taulin Cyl and informed about the Parasites, and the potential threat they posed to Trill. Gard became part of an unofficial group of watchers who kept vigil for the creatures' return. Shortly thereafter, Verjyl died, and Gard became joined with a new host, Hiziki. (DS9 novel: Unity)

"Allegro..." implies that Verjyl was in his forties at the time of that story, giving him a birthdate of around 2240.