Out of the Darkness and Into the Light
Nightmares are flaming harbingers of death. They allow only the most evil of creatures to ride them, and are never mere mounts, but rather willing partners in destruction.
Nightmares, the evil steeds of the Lower Planes, serve as mounts Demons and powerful undead lords. They look like large, powerful horses with a jet black coat. Nightmares have glowing red eyes, flaming orange nostrils, and hooves that burn like embers. Their long manes and tails are ragged and wild. They understand commands from evil riders and communicate among themselves by empathy.