Large Fiend, Neutral Evil
AC13
Initiative+2 (12)
HP68 (8d10 + 24)
SpeedWalk 60 ft., Fly 90 ft. (hover)
STR18
MOD+4
SAVE+4
DEX15
MOD+2
SAVE+2
CON16
MOD+3
SAVE+3
INT10
MOD+0
SAVE+0
WIS13
MOD+1
SAVE+1
CHA15
MOD+2
SAVE+2
Damage ImmunitiesFire
SensesPassive Perception 11
LanguagesUnderstands Abyssal, Common, and Infernal but can't speak
CRCR 3 (XP 700; PB +2)
Traits
Confer Fire Resistance. The nightmare can grant Resistance to Fire damage to a rider while it is on the nightmare.
Illumination. The nightmare sheds Bright Light in a 10-foot radius and Dim Light for an additional 10 feet.
Actions
Hooves. Melee Attack Roll: +6, reach 5 ft. Hit: 13 (2d8 + 4) Bludgeoning damage plus 10 (3d6) Fire damage.
Ethereal Stride. The nightmare and up to three willing creatures within 5 feet of it teleport to the Ethereal Plane from the Material Plane or vice versa.
Found on p.226 of MM2025 (Free Rules)