In the 24th century, the Cheka were attempting to enslave the Yrythny, as they had previously done with other species, and had blockaded their homeworld Vanimel with undetectable nanobots that emerge from subspace to disable starships. In 2376, the crew of the USS Defiant were able to help the Yrythny find a defense against the Cheka and their weaponry. (DS9 - Mission Gamma novel: This Gray Spirit)