Ol' Red CR: 5

Large undead, lawful neutral

Armor Class: 15

Hit Points: 68 (9d10 + 18)

Speed: 50 ft

STR

17 +3

DEX

12 +1

CON

14 +2

INT

9 -1

WIS

13 +1

CHA

6 -2

Skills:

Perception +5

Damage Resistances: Bludgeoning, Piercing, & Slashing from Nonmagical Attacks

Damage Immunities: Cold, Necrotic, Poison

Condition Immunities: Charmed, Exhaustion, Frightened, Grappled, Paralyzed, Petrified, Poisoned, Prone, Restrained

Senses:

Darkvision 60', Passive Perception 15

Languages: Understands Common but can't speak

Challenge Rating: 5 ( 1800 XP)

Proficiency Bonus: +2

Ethereal Awareness. Ol' Red mastiff can see ethereal creatures and objects.

Keen Hearing & Smell. Ol' Red has advantage on Wisdom (Perception) checks that rely on hearing or smell.

Pack Tactics. Ol' Red 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 & the ally isn't incapacitated.

Actions

Bite. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 8 (1d10 + 3) piercing damage plus 9 (2d8) necrotic damage.

Grave Breath (Recharge 5–6). Ol' Red exhales a fetid miasma in a 15-foot cone. Each creature in that area must make a DC 12 Dexterity saving throw, taking 27 (6d8) necrotic damage on a failed save, or half as much damage on a successful one.