The Chalchaj 'qmey (translated: Children of Heaven) were a race of genetically-engineered Klingon-Romulan hybrids from the planet Chal. Their species name, unwieldy to most non-Klingon speakers, was often shortened to simply Chal, and they generally accepted this colloquialism.
The Chalchaj 'qmey were created as part of a joint colonial effort between the Klingon Empire and the Romulan Star Empire at a time when both powers believed a devastating war with the United Federation of Planets was inevitable and they sought to breed a race of "super-soldiers." The colony was eventually abandoned by both governments, and the Chal were left to their own devices.
Physically, the Chalchaj 'qmey typically had features common to both their genetic ancestors, the Klingon-esque brow ridges, and the pointed Vulcanoid ears of the Romulans. Their skin tone, eye color and hair color represented the full range of both parent races. By wearing one's hair long, it was relatively easy for a Chal to pass as a Klingon. (TOS novel: The Ashes of Eden)
- It is unknown if the Chalchaj 'qmey posses iron- or copper-based blood, or some engineered compound of the two.