AC 13 (natural armor)
HP 93 (11d10 + 33; bloodied 46)
Speed 60 ft., fly 90 ft.
Proficiency +2; Maneuver DC 14
Damage Immunities fire
Senses passive Perception 11
Languages understands Abyssal, Common, and Infernal but can’t speak
Evil. The nightmare radiates an Evil aura.
Fiery Hooves. The nightmare sheds bright light in a 10-foot radius and dim light for an additional 10 feet. The nightmare leaves charred hoofprints.
Fire Resistance. The nightmare can grant fire resistance to a rider.
Fiery Trail. When the nightmare moves along the ground, it can choose to leave behind a trail of fire 10 feet wide and 10 feet tall, which lasts until the beginning of the nightmare’s next turn. A creature that begins its turn in the fire or enters it for the first time on a turn takes 10 (3d6) fire damage. The trail ignites flammable objects.
Telepathy. The nightmare gains telepathy with a range of 120 feet. It can telepathically communicate with the fiend that trained it over any distance as long as they are on the same plane of existence.
ACTIONS
Hooves. Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 11 (2d6 + 4) bludgeoning damage plus 7 (2d6) fire damage. If the horse moves at least 20 feet straight towards the target before the attack, the target makes a DC 14 Strength saving throw , falling prone on a failure. The nightmare can move through the space of a prone creature as long as it does not end its turn there.
Ethereal Shift (Recharge 5-6). The nightmare and a rider magically pass from the Ethereal Plane to the Material Plane or vice versa.
Combat
The nightmare charges foes, battering them with its hooves and galloping over them.
Legends and Lore
With an Arcana or Religion check, characters can learn the following:
DC 10 Though superficially similar to horses, nightmares are actually fiends. They serve as mounts to evil creatures such as demons, devils, and intelligent undead.
DC 15 Nightmares are impervious to fire and confer a measure of this protection to their riders.
DC 20 Nightmares gallop through the air as easily as they cross the ground. They can even travel back and forth between the Material and Ethereal Plane.
Some nightmares are bred in Hell for extra toughness and reliability. Archdevils give them to champions of evil, both as exceptional steeds and as spies for the champions’ infernal masters.
1–2 Charred hoofprints
3 Uncontrolled wildfire
4 The charred remains of a humanoid
5 The sound of galloping in the distance
6 A streak of fire across the sky
Nightmares are rarely encountered without a rider, except in Hell, the Abyss, or on the Ethereal Plane.
CR 3–4 nightmare
CR 5–10 fell nightmare ; 2 or 3 nightmares ; nightmare leading 1d8 + 4 skeletal warhorses
Fiends are evil-aligned creatures from Hell, the Abyss, and other cursed realms. Most fiends are demons and devils, each of which have their own subtypes and hierarchies. Some fiends, such as hell hounds , are neither demons nor devils.