Appendix B: Infernal War Machines · The Handy Haversack

Infernal war machines are vehicles built in the Nine Hells and fueled by the souls of the damned. Smaller war machines carry raiding parties or scouts. Larger, more menacing war machines can crush entire hordes of demons or deliver shock troops behind enemy lines.

Infernal war machines are made of infernal iron and bristle with spikes, blades, chains, and siege weapons. An infernal war machine’s engine roars a bass, growling rumble with an undertone of agonized screams as its furnace burns souls for fuel.

This appendix includes stat blocks for infernal war machines, rules for running and repairing them, and guidelines for handling chases in Avernus.

Stat Blocks

Stat blocks for four sample infernal war machines are presented in this appendix. An infernal war machine’s statistics function like those for creatures, with the following additional considerations.

Creature and Cargo Capacity

Creature capacity describes how many creatures can ride the infernal war machine comfortably. More creatures can fit by squeezing or by clinging to the outside of the vehicle.

Cargo capacity specifies how much cargo the infernal war machine can carry.

Armor Class

An infernal war machine is typically made of infernal iron and has an Armor Class of 19 + its Dexterity modifier. While the vehicle is not moving, attack rolls made against it have advantage.

Ability Scores

An infernal war machine has the six ability scores and corresponding modifiers. Its size and weight determines its Strength. Dexterity represents its handling and maneuverability. A vehicle’s Constitution reflects its durability and quality of construction. Infernal war machines usually have a score of 0 in Intelligence, Wisdom, and Charisma.

If an infernal war machine has a 0 in a score, it automatically fails any ability check or saving throw that uses that score.

Hit Points

An infernal war machine’s hit points can be restored by making repairs to the vehicle (see “area Repairs"). When an infernal war machine drops to 0 hit points, it ceases to function and is damaged beyond repair, and any souls trapped in the vehicle’s furnace are released to the afterlife (see “area Soul Fuel").

Damage Threshold

Infernal war machines have bulk or armor that allows them to shrug off minor hits. A vehicle with a damage threshold has immunity to all damage unless it takes an amount of damage equal to or greater than its damage threshold value, in which case it takes damage as normal. Any damage that fails to meet or exceed the vehicle’s damage threshold is considered superficial and doesn’t reduce the vehicle’s hit points.

Mishap Threshold

If an infernal war machine takes damage from a single source equal to or greater than its mishap threshold, it must roll on the Mishaps table (see “area Mishaps").

Actions Stations and Crew

An infernal war machine doesn’t have actions of its own. It relies on crew to occupy stations and use their actions to operate the vehicle’s various functions. Any option that appears in the Action Stations section of an infernal war machine’s stat block requires an action to perform.

Rules

Rules for infernal war machines are summarized below.

Magical Elements

An infernal war machine’s engine, furnace, and weapons are magical and become inoperable within an antimagic field. When the engine or furnace comes into contact with such an effect, the infernal war machine shuts down and can’t be restarted until both the engine and the furnace are free of the field.

Opportunity Attacks

Infernal war machines provoke opportunity attacks as normal. When an infernal war machine provokes an opportunity attack, the attacker can target the vehicle or any creature riding on or inside it that doesn’t have total cover and is within reach.

Action Stations

A creature can use an action of the station it’s occupying. Once a creature uses a station’s action, that action can’t be used again until the start of that creature’s next turn. Only one creature can occupy each station.

A creature not occupying an action station is either in a passenger seat or clinging to the outside of the vehicle. It can take actions as normal.

Helm

The helm of an infernal war machine is a chair with a wheel, levers, pedals, and other controls. The helm requires a driver to operate. An infernal war machine with no driver automatically fails Dexterity saving throws.

A driver proficient with land vehicles can add its proficiency bonus to ability checks and saving throws made using the infernal war machine’s ability scores.

Drive

While the infernal war machine’s engine is on, the driver can use an action to propel the vehicle up to its speed or bring the vehicle to a dead stop. While the vehicle is moving, the driver can steer it along any course.

If the driver is incapacitated, leaves the helm, or does nothing to alter the infernal war machine’s course and speed, the vehicle moves in the same direction and at the same speed as it did during the driver’s last turn until it hits an obstacle big enough to stop it.

Bonus Actions

As a bonus action, the driver can do one of the following:

Start the infernal war machine’s engine or shut it off.
Cause the infernal war machine to take the Dash or Disengage action while the vehicle’s engine is running.
Insert a soul coin or pour a flask of demon ichor into the engine’s furnace (see “area Soul Fuel” and “area Demon Ichor Boost” below).

Weapon Stations

Each of an infernal war machine’s weapons takes up a station on the vehicle.

One weapon can be replaced with another (see “area Alternative Weapon Stations"), provided the crew requirement needed to operate the replacement weapon is the same.

Soul Fuel

The engine at the heart of every infernal war machine has a furnace fueled by Soul Coin. Among the vehicle’s helm controls is a narrow slot into which Soul Coin can be fed. Soul Coin placed in this slot tumble into the furnace, which is two size categories smaller than the vehicle containing it.

An infernal war machine’s furnace consumes a soul coin instantly, expending all the coin’s remaining charges at once and destroying the coin in the process. The soul trapped in the coin becomes trapped in the furnace instead, powering the infernal war machine for a duration determined by how many charges the soul coin had when it was consumed: 1 charge, 24 hours; 2 charges, 48 hours; 3 charges, 72 hours. If it’s still trapped in the furnace when this duration ends, the soul is destroyed. Not even divine intervention can restore a soul destroyed in this manner.

Regardless of its size, a furnace can hold any number of souls, their screams of anguish audible out to a range of 60 feet. Each new soul fed to the furnace adds more fuel to the vehicle, allowing it to run longer.

Demon Ichor Boost

Pouring a flask of demon ichor into an infernal war machine’s furnace increases the vehicle’s speed by 30 feet for 1 minute. While the vehicle’s speed is increased in this way, roll a d20 at the start of each of the driver’s turns. On a 1, the vehicle suffers the Furnace Rupture result on the Mishaps table (see “area Mishaps").

Devil’s Ride
Tormentor
Demon Grinder
Scavenger

Mishaps

Roll on the Mishaps table when one of the following occurs to an infernal war machine while it’s in motion:

The infernal war machine takes damage from a single source equal to or greater than its mishap threshold.
The infernal war machine fails an ability check (or its driver fails an ability check using the vehicle’s ability) by more than 5.

If a mishap has a repair DC, the mishap can be ended by making repairs to the vehicle (see “area Repairs” below).

Mishaps

d20	Mishap	Repair DC
1	Engine Flare. Fire erupts from the engine and engulfs the vehicle. Any creature that starts its turn on or inside the vehicle takes 10 (3d6) fire damage until this mishap ends.	15 (Dex)
2–4	Locked Steering. The vehicle can move in a straight line only. It automatically fails Dexterity checks and Dexterity saving throws until this mishap ends.	15 (Str)
5–7	Furnace Rupture. The vehicle’s speed decreases by 30 feet until this mishap ends.	15 (Str)
8–10	Weapon Malfunction. One of the vehicle’s weapons (DM’s choice) can’t be used until this mishap ends. If the vehicle has no functioning weapons, no mishap occurs.	20 (Str)
11–13	Blinding Smoke. The helm station fills with smoke and is heavily obscured until this mishap ends. Any creature in the helm station is blinded by the smoke.	15 (Dex)
14–16	Shedding Armor. The vehicle’s damage threshold is reduced by 10 until this mishap ends.	15 (Str)
17–19	Damaged Axle. The vehicle grinds and shakes uncontrollably. Until the mishap ends, the vehicle has disadvantage on all Dexterity checks, and all ability checks and attack rolls made by creatures on or inside the vehicle have disadvantage.	20 (Dex)
20	Flip. The vehicle flips over, falls prone, and comes to a dead stop in an unoccupied space. Any unsecured creature holding on to the outside of the vehicle must succeed on a DC 20 Strength saving throw or be thrown off, landing prone in a random unoccupied space within 20 feet of the overturned vehicle. Creatures inside the vehicle fall prone and must succeed on a DC 15 Strength saving throw or take 10 (3d6) bludgeoning damage.	None

Vehicular Exhaustion

The harsh conditions of the Nine Hells can cause an infernal war machine to stop functioning properly, until it eventually breaks down. Such wear and tear can be represented using exhaustion, as described in exhaustion of the Player’s Handbook, with these modifications:

When an infernal war machine reaches exhaustion level 6, its hit points drop to 0, and the vehicle breaks down.
The only way to remove the effects of exhaustion on an infernal war machine is to repair the vehicle.

Repairs

When an infernal war machine is damaged, suffers a mishap, or gains one or more levels of exhaustion, a creature can attempt to make repairs to the vehicle. The creature making the repairs must meet the following criteria:

The creature can’t operate the vehicle’s helm or one of its weapon stations while making repairs.
The creature must be within reach of the damaged area in need of repair.
The creature must have the right tools for the job (smith’s tools or tinker’s tools, for example).

Before beginning repairs, a creature must decide whether the repairs are aimed at ending a mishap, removing a level of exhaustion, or restoring the damaged vehicle’s hit points. Each option is discussed below.

End a Mishap

A creature can use its action to make an ability check based on the nature of the mishap (see the area Mishaps table), with disadvantage if the vehicle is moving. The creature adds its proficiency bonus to the check if it’s proficient with the tools used to make the repairs. A successful check ends the mishap. A mishap with no repair DC can’t be repaired.

Remove Exhaustion

If the infernal war machine has one or more levels of exhaustion, a creature can spend 1 hour or more trying to reduce the vehicle’s exhaustion level. The vehicle must be stationary, and the creature must have spare parts to make the necessary repairs. After 1 hour of repair work, the creature makes a DC 15 Intelligence check, adding its proficiency bonus to the check if it’s proficient with the tools used to make repairs. If the check succeeds, the vehicle’s exhaustion level decreases by 1. If the check fails, the vehicle’s exhaustion level remains unchanged, though the repair can be attempted again using the same replacement parts.

Restore Hit Points

If the infernal war machine has taken damage but has at least 1 hit point, a creature can spend 1 hour or more trying to patch the hull and replace damaged parts. The vehicle must be stationary, and the creature must have the spare parts to make the necessary repairs. After 1 hour of repair work, the creature makes a DC 15 Dexterity check, adding its proficiency bonus to the check if it’s proficient with the tools used to make repairs. If the check succeeds, the vehicle regains 2d4 + 2 hit points. If the check fails, the vehicle regains no hit points, but the repair can be attempted again using the same replacement parts.

Crashing

When an infernal war machine crashes into something that could reasonably damage it, such as an iron wall or another vehicle of its size or bigger, the infernal war machine comes to a sudden stop and takes 1d6 bludgeoning damage for every 10 feet it moved since its last turn (maximum 20d6). Whatever the vehicle struck takes the same amount of damage. If this damage is less than the infernal war machine’s damage threshold, the vehicle takes no damage from the crash.

Regardless of whether or not the infernal war machine takes damage, each creature on or inside the vehicle when it crashes must make a DC 15 Strength saving throw, taking 1d6 bludgeoning damage for every 10 feet the vehicle moved since its last turn (maximum 20d6), or half as much damage on a successful save.

Crashing into Creatures

An infernal war machine can crash into a creature by entering its space. The creature can use its reaction to attempt to get out of the vehicle’s way, doing so and taking no damage with a successful DC 10 Dexterity saving throw. If the saving throw fails, the vehicle slams into the creature and deals 1d6 bludgeoning damage to the creature for every 10 feet the vehicle moved since its last turn (maximum 20d6).

An infernal war machine that is at least two size categories bigger than the creature it crashed into can continue moving through that creature’s space if the infernal war machine has any movement left. Otherwise, the vehicle comes to a sudden stop, and each creature on or inside the infernal war machine when it crashes must make a DC 15 Strength saving throw, taking 1d6 bludgeoning damage for every 10 feet the vehicle moved since its last turn (maximum 20d6), or half as much damage on a successful save.

Falling

When an infernal war machine goes over a cliff or otherwise falls, the vehicle and all creatures on or inside it take damage from the fall as normal (1d6 bludgeoning damage per 10 feet fallen, maximum 20d6) and land prone.

Fiendish Variations

Devils work tirelessly to create new and more powerful engines of war to stem the demonic tides flowing out of the Abyss. In addition, infernal war machines can be equipped with more unusual weapons and armor.

Alternative Weapon Stations

One weapon station can be switched for another, but the infernal war machine can’t have more weapon stations than it normally has. A handful of alternative weapon stations are described in this section.

Acidic Bile Sprayer
Flamethrower
Infernal Screamer
Styx Sprayer

Armor Upgrades

An infernal war machine can receive one armor upgrade. Sample upgrades are described below.

Canian Armor
Gilded Death Armor
Soul Spike Armor

Magical Gadgets

Devils like to bedeck their infernal war machines with fiendish gadgets to bedevil foes. Such gadgets are usually activated from the helm station.

Necrotic Smoke Screen
Teleporter

Chases on Avernus

Using the guidelines in chapter 8 of the Dungeon Master’s Guide and the Avernus Chase Complications table, you can build a chase that incorporates hazards unique to Avernus. Use an infernal war machine’s Constitution modifier to determine how many times it can Dash during a chase.

When a chase complication forces the vehicle to make an ability check, or the driver to make an ability check using the vehicle’s ability, a mishap occurs if the check fails by 5 or more (see “area Mishaps").

Avernus Chase Complications

d20	Complication
1–2	You drive past a creature native to Avernus, and it chases after you. The DM chooses the creature.
3	A fire tornado, 300 feet high and 30 feet wide at its base, crosses your path. The vehicle avoids the tornado with a successful DC 15 Dexterity saving throw. Otherwise, the tornado envelops the vehicle, and each creature on or inside it that doesn’t have total cover must make a DC 18 Dexterity saving throw, taking 99 (18d10) fire damage on a failed save, or half as much damage on a successful one.
4	A swirling cloud of dust envelops the vehicle. Any creature on or inside the vehicle that doesn’t have total cover is blinded by the dust until the start of its next turn unless it’s using some kind of protective eyewear.
5	Natural pillars of rock can grant cover as the vehicle swerves between them. The driver of the vehicle can make a DC 15 Dexterity check using the vehicle’s Dexterity. On a success, the pillars provide three-quarters cover against attacks from other vehicles until the start of the driver’s next turn.
6	Your vehicle drives into a herd of Lemure, manes, or other fiends. The vehicle must make a DC 15 Strength or Dexterity check (driver’s choice) to plow through the herd unimpeded. On a failed check, the herd counts as 30 feet of difficult terrain.
7	The vehicle drives off a 10-foot-high ledge and comes crashing down. Any unsecured creature on the outside of the vehicle must succeed on a DC 15 Dexterity saving throw or tumble off, taking normal damage from the fall and landing prone in an unoccupied space on the ground.
8	Uneven ground threatens to slow your vehicle’s progress. The vehicle must make a DC 10 Dexterity check to navigate the area. On a failed check, the ground counts as 60 feet of difficult terrain.
9	Derelict infernal war machines dot the landscape, rusted beyond repair and half buried in the dust. If the vehicle uses Dash this turn, the driver must succeed on a DC 10 Dexterity check using the vehicle’s Dexterity or crash into one of the derelict infernal war machines (see “area Crashing").
10	Part of the ground gives way underneath the vehicle, causing it to roll over. The vehicle must succeed on a DC 10 Dexterity saving throw. On a success, the vehicle rolls into an upright position and can continuing moving. On a failure, the vehicle lands prone, either upside down or on its side, after coming to a dead stop. When the vehicle rolls, any unsecured creature holding on to the outside of it must succeed on a DC 20 Strength saving throw or tumble off, landing prone in an unoccupied space within 20 feet of the overturned vehicle.
11–20	No complication.