The Call was a magical effect that effected all warlocks between the Night of Madness in YS 5202 until the arrival of the Response in 5236. This Call emanated from the Aldagmor Source of warlockry, and seems to be what which initially attuned humans to warlockry. Individuals who became too attuned to the Call would find their will overwhelmed by it and would seek to go to Aldagmor by the quickest means available to them. As using warlockry continued to make an individual more attuned to the source, and thus more powerful, this became the expected fate of all warlocks. As a warlock became more attuned to the Call it invaded more of their thoughts, creating nightmares during their sleep and distracting them with a constant indecipherable whispering while conscious.
Prior to the end of the Call it was unknown what happened to warlocks who were overcome by it. Because of the disturbing nature of the images projected by the Call it was assumed that the warlocks who answered were slain or subject to some form of torment. With the end if the Call it has been discovered that Called warlocks were instead caught in a magical stasis field the Aldagmor Source had created to protect itself.