Mordenkainen's Tome of Foes

HELLFIRE ENGINE

Hellfire engines are semiautonomous bringers of de-

struction. Amnizus and other devilish generals hold

them in reserve until they are needed to repel an incur-

sion by demons or crusading mortals, but occasionally

one of these mechanical and magical hybrids gets loose,

driven berserk by its need to destroy.

Many Forms, One Purpose. Hellfire engines take

many forms, but all of them have one purpose: to

mow down foes in waves. They are incapable of

subtlety or trickery, but the ir destructive capability

is immense.

Soul Trapping. Mortal creatures slain by hellfire

engines are doomed to join the infernal legions

in mere hours unless powerful magic-wielders in-

tervene on their behalf. The archdukes would like

nothing better than to modify this magic so it works

against demons, too, but that discovery has eluded

them so far.

Constructed Nature. A hellfire engine doesn't re-

quire a ir, food, drink, or sleep.

HELLFIRE ENGIN E

Huge construct, lawful evil

Armor Class 18 (natural armor)

Hit Points 2 16 (16dl2 + 112)

Speed 40 ft.

STR

20 (+5)

DEX

16 (+3)

CON

24 (+7)

INT

2 (-4)

Saving Throws Dex +8, Wis +5, Cha +O

WIS

10 (+O)

CHA

l (-5)

Damage Resistances cold, psychic; bludgeoning, piercing, and

slashing from nonmagical attacks that aren't silvered

Damage Immunities fire, poison

Condition Immunities charmed, deafened, exhaustion,

frightened, paralyzed, poisoned, unconscious

Senses darkvision 120 ft., passive Perception 10

Languages understands Infernal but can't speak

Challenge 16 (15,000 XP)

Immutable Form. The hellfire engine is immune to any spell or

effect that would alter its form.

Magic Resistance. The hellfire engine has advantage on saving

throws against spells and other magical effects.

ACTIONS

Flesh-Crushing Stride. The hellfire engine moves up to its

speed in a straight line. During this move, it can enter Large or

smaller creatures' spaces. A creature whose space the hellfire

engine enters must make a DC 18 Dexterity saving throw. On

a successful save, t he creature is pushed 5 feet to the nearest

space out of the hellfire engine' s path. On a failed save, the

creature falls prone and takes 28 (8d6) bludgeoning damage.

If the hellfire engine remains in the prone creature's space,

the creature is also restrained until it's no longer in the same

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space as the hellfire engine. While restrained in this way, the

creature, or another creature within 5 feet of it, can make a DC

18 Strength check. On a success, the creature is shunted to an

unoccupied space of its choice within 5 feet of the hellfire en-

gine and is no longer restrained.

Hellfire Weapons. The hellfire engine uses one of the follow-

ing options:

Bonemelt Sprayer. The hellfire engine spews acidic flame in a

60-foot cone. Each creature in the cone must make a DC 20

Dexterity saving throw, taking 11 (2dl0) fire damage plus 18

(4d8) acid damage on a failed save, or half as much damage

on a successful one. Creatures that fail the saving throw are

drenched in burning acid and take 5 (ldlO) fire damage plus

9 (2d8) acid damage at the end of their turns. An affected

creature or another creature within 5 feet of it can take an

action to scrape off the burning fuel.

Lightning Flail. Melee Weapon Attack: +11 to hit, reach 15 ft.,

one creature. Hit: 18 (3d8 + 5) bludgeoning damage plus

22 (5d8) lightning damage. Up to three other creatures of

the hellfire engine's choice that it can see within 30 feet of

the target must each make a DC 20 Dexterity saving throw,

taking 22 (5d8) lightning damage on a failed save, or half as

much damage on a successful one.

Thunder Cannon. The hellfire engine targets a point within 120

feet of it that it can see. Each creature within 30 feet of that

point must make a DC 20 Dexterity saving throw, taking 27

(5dl0) bludgeoning damage plus 13 (2dl2) thunder damage

on a failed save, or half as much damage on a successful one.

If the chosen option kills a creature, t he creature's soul rises

from the River Styx as a lemure in Avernus in ld4 hours. If the

creature isn't revived before then, only a wish spell or killing the

lemure and casting true resurrection on the creature's original

body can restore it to life. Constructs and devils are immune to

this effect.

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CHAPTER 6 I BESTIARY