Hell Hound

Hell Hound Medium fiend, lawful evil 3 700 xp

Armor class 15 (natural armor)
Hit points 45 (7d8 + 14)
Speed 50 ft.

STR 17 (+3)
DEX 12 (+1)
CON 14 (+2)
INT 6 (-2)
WIS 13 (+1)
CHA 6 (-2)

Skills: Perception +5

Damage Immunities: fire

Senses: darkvision 60 ft., passive Perception 15

Languages: understands Infernal but can't speak it

Challenge: 3 (700 xp)

Keen Hearing and Smell. The hound has advantage on Wisdom (Perception) checks that rely on hearing or smell
.
Pack Tactics. The hound has advantage on an attack roll against a creature if at least one of the hound's allies is within 5 feet of the creature and the ally isn't incapacitated.

Actions

Bite. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 7 (1d8 + 3) piercing damage plus 7 (2d6) fire damage.

Fire Breath (Recharge 5–6). The hound exhales fire in a 15-foot cone. Each creature in that area must make a DC 12 Dexterity saving throw, taking 21 (6d6) fire damage on a failed save, or half as much damage on a successful one.