Netherworld
The Netherworld is a cold, barren plane of demons. Its landscape is abysmally murky and bleak. It is an open, desolate plain, devoid of life and blighted by hordes of demons that war endlessly. It is to this plane that the lich Teneb Trismegistus retreats when the first rays of the sun begin to snake their way across Sapience.
It was here that the demon Azmodai brought Xianty and killed him numerous times, after kidnapping him in the year 271 AF. It was also from here that Xianty's shadow self, Xian, emerged onto the Prime Material Plane to wreak havoc upon the mortals therein.
After the goddess Demeter lost Her battle of wills with the Wyrm of Worlds, Her discorporate form was cast into this plane. Under the horrors and ravages of this demonic crucible, She underwent the changes that would cause Her to emerge reborn as Melantha, Goddess of the Seasons. Eventually, thanks to a ritual led by Kalleah, the spirit of the Hazel with the help of a small cadre of forestals, Melantha managed to break free of this plane.
The Netherworld is not to be confused with the Underworld or Underrealm.