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.

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.

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 "Soul Fuel'" and "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 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 coins. Among the vehicle's helm controls is a narrow slot into which soul coins can be fed. Soul coins 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 a Furnace Rupture.

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 appendix A 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, 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. 1f 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 ld6 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 ld6 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 ld6 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 ld6 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 {ld6 bludgeoning damage per 10 feet fallen, maximum 20d6) and land prone.