Kerberos

Large fiend, lawful neutral

Armor Class 19 (natural armor)
Hit Points 127 (15d10 + 45)
Speed 50 ft.

STR	DEX	CON	INT	WIS	CHA
19 (+4)	13 (+1)	17 (+3)	4 (-3)	18 (+4)	10 (+0)

Damage Immunities acid, poison
Condition Immunities poisoned
Skills Perception +59
Senses truesight 120 ft., passive Perception 169
Languages –
Challenge 15 (13,000 XP)

Special Traits

• Keen Hearing and Smell. The kerberos has advantage on Wisdom (Perception) checks that rely on sound or smell.
• Multiple Heads. The kerberos has fifty heads. While it has more than one head, the kerberos has advantage on saving throws against being blinded, charmed, deafened, frightened, stunned, and knocked unconscious. Whenever the kerberos takes 2 or more damage in a single turn, one of its heads dies. If all its heads die, the kerberos dies. t one of its heads is awake.
• Pounce. If the kereberos moves at least 20 feet straight toward a creature and then hits it with a claw attack on the same turn that target must succeed on a DC 17 Strength saving throw or be knocked prone. If the target is knocked prone, the kerberos can make two attacks-one with its bite and one with its snakes-against it as a bonus action.
• Reactive Heads. For each head the kerberos has beyond one, it gets an extra reaction that can be used only for opportunity attacks.
• Sunlight Sensitivity. While in sunlight, the kerberos has disadvantage on attack rolls, as well as on Wisdom (Perception) checks that rely on sight.
• Wakeful. While the kerberos sleeps, at least one of its other heads are awake.

Actions

• Multiattack. The kerberos makes five attacks: three with its bite, one with its claw, and one with its snakes.
• Bite. Melee Weapon Attack: +9 to hit, reach 5 ft., one target. Hit: 7 (1d6 + 4) piercing damage plus 3 (1d6) acid damage.
• Claw. Melee Weapon Attack: +9 to hit, reach 5 ft., one target. Hit: 7 (1d6 + 4) slashing damage.
• Snakes. Melee Weapon Attack: +9 to hit, reach 10 ft., one creature. Hit: 7 (1d6 + 4) piercing damage, and the target must make a DC 16 Constitution saving throw, taking 21 (6d6) poison damage on a failed save, or half as much damage on a successful one.
• Terrifying Howl. The kerberos howls. Any beast or humanoid within 300 feet of the kerberos and able to hear its howl must succeed on a DC 17 Wisdom saving throw or be frightened for 1 minute. A frightened target can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success. If a target’s saving throw is successful or the effect ends for it, the target is immune to any kerberos’ Terrifying Howl for the next 24 hours.
• Acid Breath (Recharge 5-6). The kerberos exhales acid in a 30-foot line that is 5 feet wide. Each creature in that line must make a DC 14 Dexterity saving throw, taking 49 (11d8) acid damage on a failed save, or half as much damage on a successful one.

About

This large three-headed mastiff is noteworthy for more than just its extra forequarters. Its tail is that of a snake and its entire neck is ringed with smaller snakes. Its claws are that of a lion.

A kerberos is about 5 feet tall at the shoulder, nearly 10 feet long, and weighs about 4,000 pounds.

Guardians of the Dead. Kerberos hounds are greatly coveted as faithful guardians of dark places, and their hearing is such that they can even hear ghosts. To that end they are often used as guardians of the underworld.