The Qianyu Clan was one of the numerous and minute tribes that flocked around the periphery of the Red Moon Camp, akin to black droplets. They may have originally been humans, but drawn by the great Crimson Moon, they threw themselves into this faction, offering their bodies and hearts, and gradually evolved the unique racial ability specific to the Qianyu Clan—the Feather Mark.
The feathers they plucked from themselves could act as extensions of their own antennae, serving to collect external information on their behalf, albeit in a limited fashion.
Location, sound, light, shadow, and so forth.
The farther the distance, the less information they could collect. In theory, across half the Great Domain, the Qianyu Clan would no longer be able to sense their own feathers.