Source: Monster Manual (2024) p. 226, FRHoF. Available in the SRD and the Free Rules (2024)
Nightmare
Dread Steed of the Lower Planes
Habitat. Planar (Lower Planes)
Treasure. None
Nightmares resemble horses with flaming manes, burning hooves, and smoldering eyes. They terrorize weaker creatures and often ally with denizens of the Lower Planes in committing evil acts. These supernatural horses can innately travel between the Ethereal Plane and the Material Plane, and many know the locations of portals to the Lower Planes, the Shadowfell, and other sinister realms.
Nightmares’ speed, resilience, and ability to gallop between planes of existence make them steeds coveted by evildoers. Roll on or choose a result from the Nightmare Riders table to inspire what might employ a nightmare steed.
Nightmare Riders
dice: 1d6
The Nightmare Carries…
1
The champion or messenger of an evil deity.
2
A group of joyriding imps or quasits.
3
An innocent soul trapped on the wild Fiend.
4
A lore-hunting mage, cultist, or lich.
5
A night hag herding larvae between planes.
6
A wicked cavalier, such as a death knight, an erinyes, an incubus, or a vampire.