The Singers were mentioned by Mordenkai, who called himself a former Listener of theirs. He says that they would speak to him, a chorus of voices, and tell him what to do. They extended his lifespan, and may have given him other supernatural powers as well. He does not remember the things that he was asked to do, but seemed to grow fearful.
The latest Listener is unknown, but Mordenkai believes that they are currently in the city of Sentra.
The Singers match dark tales of elvish bogeymen called ustasi duyarti (which roughly translates to "puppet master"). They sang to their victims to force them to do things against their will.