The Defiler

The Defiler not only attack beings it could find, but it attempted to burn and level every forest and taint every aspect of the lands it touched so nothing could live there again attempting to spread supernatural poisons around Scarterra and possibly Scaraqua.   While Void Demons did not hesitate for a second to attack any Fair Folk or Sprite they encountered in the material plane, the Defiler seems to be the only Demon Lord that made attack the Fae a priority.   It is not clear whether the Defiler itself was able to enter Fae Home but the Defiler certainly captured a great many Faerie gateways and sent minions to attack Fae Home, hoping to spread supernatural by poisoning the arteries that connected Fae Home, the material plane, and the The Elemental Plane.   The contemporary Fair Folk certainly curse the Defiler's memory and some bregudgingly admit that their land has yet to fully heal from the damages inflicted upon it by the Defiler.   It is not clear if the Defiler managed to cause permanent damage to the Elemental Plane but its army did have a lot of twisted elementals supporting it, easily more than any other Demon Lord.   While the damage it inflicted was unspeakably awful, the Defiler’s reign of terror was actually fairly short of any demon lord. An alliance of spirits (especially but not exclusively Korus affiliated spirits) and various fey creatures engaged his army and slew the Defiler.   There are pockets of tainted land and tainted sea remaining from the Defiler's effort remaining in the current era of the Third Age but they are relatively hard to find. It is believed that Mera has been using her divine comb to cleanse the poison from Scarterra a tiny bit at a time, slow and steady for thousands of years.