Yrythny
- Appearance: Amphibious
- Leathery skin
- Skin tone ranges from dark brown to greenish-gray to yellow-green (DS9 Novel: Mission Gamma: This Gray Spirit)
- Patterned with stripes or spots (DS9 Novel: Mission Gamma: This Gray Spirit)
- Hairless forms (DS9 Novel: Mission Gamma: This Gray Spirit)
- Wide mouths (DS9 Novel: Mission Gamma: This Gray Spirit)
- Black eyes (DS9 Novel: Mission Gamma: This Gray Spirit)
- Frog-like skin pockets below jaw inflating and deflating as they breathe (DS9 Novel: Mission Gamma: This Gray Spirit)
- Cartilage ridges in place of ears (DS9 Novel: Mission Gamma: This Gray Spirit)
- Nictating membranes over eyes (DS9 Novel: Mission Gamma: This Gray Spirit)
- Leathery skin
- Homeworld: Vanìmel
- Biological notes
- Uplifted by unknown species from non-sentient amphibians (DS9 Novel: Mission Gamma: This Gray Spirit)
- Genetic sequence granting sentience known by Yrythny as the "turn key" (DS9 Novel: Mission Gamma: This Gray Spirit)
- Skin health is dependent on high levels of humidity (DS9 Novel: Mission Gamma: This Gray Spirit)
- Mating time hits suddenly, marked by eruption of blue starburst pattern on palms (DS9 Novel: Mission Gamma: This Gray Spirit)
- Uplifted by unknown species from non-sentient amphibians (DS9 Novel: Mission Gamma: This Gray Spirit)
- Cultural notes
- Yrythny food
- Yrythny faith
- Focused on worship of the Other (DS9 Novel: Mission Gamma: This Gray Spirit)
- Society divided into two castes (DS9 Novel: Mission Gamma: This Gray Spirit)
- Houseborn (DS9 Novel: Mission Gamma: This Gray Spirit)
- Those who return to their parents' spawning grounds after hatching (DS9 Novel: Mission Gamma: This Gray Spirit)
- Wanderers (DS9 Novel: Mission Gamma: This Gray Spirit)
- Those who fail to return to their parents' spawning grounds (DS9 Novel: Mission Gamma: This Gray Spirit)
- Believed less intelligent, capable as a result (DS9 Novel: Mission Gamma: This Gray Spirit)
- Houseborn (DS9 Novel: Mission Gamma: This Gray Spirit)
- Members of romantic unions known as consorts (DS9 Novel: Mission Gamma: This Gray Spirit)
- Technological notes
- By the 24th century, at approximately the equivalent of 22nd century Sol-local technological development (DS9 Novel: Mission Gamma: This Gray Spirit)