The Illarhi were a primitive humanoid race that lived on Illarh. The Illarhi had copper-colored skin, mossy white hair, shiny black eyes, and bubbles on their cheeks that allowed them to hear.

In 2373, the Illarhi allowed themselves to be conquered without a fight by Jem'Hadar forces under the command of the Vorta Sejeel. The Jem'Hadar forces were removed shortly afterward by Starfleet. (STA short story: "What Dreams May Come")