At the estate sale of one wealthy merchant (who happened to be an Secret Evil Cultist) someone found several lengths of black silk cord, the kind that is used for trim and piping. A local seamstress purchased those odd lengths and the remaining bolt cheap and turned out two or three cloaks using the thin black silk cord as trim.
Misfortune has followed the owners of the cloaks. Sure some of their enemies have died grusome deaths and certain tasks have magically been performed, but most of their families and loved ones have died or been injured after a simple disagreement. Many owners of the cloaks have died soon after loosing loved ones (probably after saying, they no longer wished to live without their loved one).
The cut cords were enchantments. They were “leashes” used to control semi-mindless undead/ demonoids. These creatures spend much time in the caves and sewers not far from the estate where they were penned long ago. The creatures are still leashed and must obey those who hold those knotted cords. (they are the collar cords for the three cloaks). They follow any commands to do harm or task. These command are given innocently these days.
Imagine being mad and saying, “I hate that man. I wish he went away”. A day or so later he would disappear as the monsters kidnap him and keep him in the pen with them. When he dies, they eat him. Say, “Go to Hell” and the monsters will drag them as close as they can. “I wish someone would clean up this mess… ” and sometime later a monster will creep in and do a pretty bad job of cleaning up.
Few understand what power they possess. They accidently visit death and mayhem to those around them. Some do understand the power, and they are dangerous… of course they will do more death and mayhem but for “constructive purposes”.