During the battles between the Children of the Forest and the People of El-Rah, the “Demons” as people had taken to calling them were said to have captured and tortured many citizens of El-Rah. They were said to have dragged them back to the Wandering Woods where they would either die or be tortured beyond the limits of what their body could take.
If they did not die then they were said to lose their minds, becoming shells of what they once were. This allowed the Children of the Forest to change them into something else entirely.
A mark would be placed on the neck or chest of the victim binding their will to the Children of the Forest. This would allow them to control this person entirely, the only indication of this process was the mark placed upon their skin. They were known as Children of Sorrow, and they were sent back into El-Rah to act as spies among their own. The Children of the Forest were said to be able to whisper directly into the minds of the Children of Sorrow and extract all they had learned. While difficult to remove this spell from the child of sorrow, there were several reports on mages succeeding in restoring the persons own free will. However the person will still never recover fully,in many cases they would take their own life as they were unable to live with the tortures that they endured, only the most resilient of people were able to overcome the sorrows of their past and make a full recovery.