Echo-Fauna is the collective term for the animal life native to Xylos. Because the planet's atmosphere is dense and foggy, and the Whispering Skies provide constant noise, these animals have evolved to prioritize sound over sight.
Most Echo-Fauna do not have eyes. Instead, they possess complex radar-dish ears and sensitive skin membranes that detect air pressure changes. A prime example is the "Resonance Wolf," a predator that can project a sonic click to stun prey. These creatures are studied under Resonant Biology.
Echo-Fauna are highly sensitive to Harmonic Shielding. The artificial frequencies emitted by human cities cause them pain, driving them away from settlements. However, when shields fail, swarms of Echo-Fauna often attack, drawn by the sudden silence.
Poachers hunt Echo-Fauna for their auditory ossicles, which are believed (incorrectly) to cure deafness when ground into powder.