Sources
CR
Type
Size
Alignment
Movement

Merregon

Medium Fiend (devil), Lawful Evil

Armor Class 16 (natural armor)
Hit Points 45 (6d8 + 18)
Speed 30 ft.
STR
18
+4
DEX
14
+2
CON
17
+3
INT
6
-2
WIS
12
+1
CHA
8
-1
Damage Resistances cold; bludgeoning, piercing, slashing, from nonmagical attacks that aren't silvered
Damage Immunities fire, poison
Condition Immunities Frightened, Poisoned
Senses darkvision 60 ft., passive Perception 11
Languages understands Infernal but can't speak, telepathy 120 ft.
Challenge 4 (1,100 XP)

Traits

Devil's Sight. Magical darkness doesn't impede the merregon's darkvision.

Magic Resistance. The merregon has advantage on saving throws against spells and other magical effects.

Actions

Multiattack. The merregon makes three Halberd attacks.

Halberd. Melee Weapon Attack: +6 to hit, reach 10 ft., one target. Hit:9 (1d10 + 4) slashing damage.

Heavy Crossbow. Ranged Weapon Attack: +4 to hit, range 100/400 ft., one target. Hit:7 (1d10 + 2) piercing damage.

Reactions

Loyal Bodyguard. When another Fiend within 5 feet of the merregon is hit by an attack roll, the merregon causes itself to be hit instead.

Lore

The souls of fallen soldiers, mercenaries, and bodyguards who served evil without reservation often find everlasting servitude in the Nine Hells as merregons. These faceless foot soldiers are the Hells' legionnaires, tasked with protecting their infernal plane and its rulers against intruders.