Sources
CR
Type
Size
Alignment
Movement

Erinyes

Medium Fiend (devil), Lawful Evil

Armor Class 18 (plate armor)
Hit Points 153 (18d8 + 72)
Speed 30 ft., fly 60 ft.
STR
18
+4
DEX
16
+3
CON
18
+4
INT
14
+2
WIS
14
+2
CHA
18
+4
Saving Throws DEX +7, CON +8, WIS +6, CHA +8
Damage Resistances cold; bludgeoning, piercing, slashing, from nonmagical attacks that aren't silvered
Damage Immunities fire, poison
Condition Immunities Poisoned
Senses truesight 120 ft., passive Perception 12
Languages Infernal, telepathy 120 ft.
Challenge 12 (8,400 XP)

Traits

Hellish Weapons. The erinyes's weapon attacks are magical and deal an extra 13 (3d8) poison damage on a hit (included in the attacks).

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

Actions

Multiattack. The erinyes makes three attacks.

Longsword. Melee Weapon Attack: +8 to hit, reach 5 ft., one target. Hit:8 (1d8 + 4) slashing damage, or 9 (1d10 + 4) slashing damage if used with two hands, plus 13 (3d8) poison damage.

Longbow. Ranged Weapon Attack: +7 to hit, range 150/600 ft., one target. Hit:7 (1d8 + 3) piercing damage plus 13 (3d8) poison damage, and the target must succeed on a DC 14 Constitution saving throw or be poisoned. The poison lasts until it is removed by the lesser restoration spell or similar magic.

Reactions

Parry. The erinyes adds 4 to its AC against one melee attack that would hit it. To do so, the erinyes must see the attacker and be wielding a melee weapon.

Lore

Devils personify tyranny, with a totalitarian society dedicated to the domination of mortal life. The shadow of the Nine Hells of Baator extends far across the multiverse, and Asmodeus, the dark lord of Nessus, strives to subjugate the cosmos to satisfy his thirst for power. To do so, he must continually expand his infernal armies, sending his servants to the mortal realm to corrupt the souls from which new devils are spawned.