Specifically in regard to the effects of a hit with an adamantine weapon, would a hit with one turn into a critical hit? I know it's a vehicle but it's powered by souls and has a stat block like a creature would have. I'm going to be DMing Descent into Avernus soon and I want to make sure I look into anything that could come up during play.


3 Answers 3


Yes, Infernal War Machines are objects. Allowing for adamantine weapons to score automatic critical hits.

In the Player's Handbook, in chapter 9, under the section 'Making an Attack' (page 193), there are 3 listed options for targets: a creature, an object, or a location.

In the Dungeon Master's Guide, in chapter 8, under the section 'Objects', the subsection 'Damage Thresholds' (page 247) says:

Big objects such as castle walls often have extra resilience represented by a damage threshold.

Under the subsection 'Hit Points' (page 247), there is a table of suggested hit points by object size, within which is a cart, listed as a land vehicle, meaning that vehicles are objects.

Also in the Dungeon Master's Guide, in chapter 5, under the section 'Unusual Environments' (page 119), there is a table of vehicles, most of which featuring a damage threshold, reaffirming that ships and other vehicles, especially those with such a threshold, do count as objects.

Each of the vehicles present in Descent into Avernus is also listed as a vehicle, and also lists a damage threshold alongside their hit points, which means they would also fit under the category of 'object' for attack and damage purposes.

  • 2
    \$\begingroup\$ How would you handle the quote from the DMG "For the purpose of these rules, an object is a discrete. inanimate item like a window, door, sword, book, table, chair, or stone, not a building or a vehicle that is composed of many other objects." which Jeremy Crawford has said applies in circumstances besides just hit points? \$\endgroup\$ Oct 3, 2019 at 2:04
  • \$\begingroup\$ @Medix2 Due to that sentence, I initially thought the answer to this question was 'no', however, that same section 'Objects' then contains the info referenced in my answer (cart listed under 'Hit Points'; and the 'Damage Threshold'). Given that the 'Objects' section explicitly names a vehicle for object hit points, and damage thresholds are only present in vehicles from what I found (I think buildings too), it would seem that sentence it directly contradicted by example. 1/2 \$\endgroup\$
    – Journer
    Oct 3, 2019 at 14:12
  • \$\begingroup\$ @Medix2 With it apparently contradicted by example, it would seem to be an error not caught in review, or a more narrowly focused statement, without clarification. In either case, it is outweighed by the examples in the same section, so I chose not to cause confusion by mentioning a non-supported contradictory statement. 2/2 \$\endgroup\$
    – Journer
    Oct 3, 2019 at 14:16

They are vehicles, but whether or not it is an object may be up to a DM

The stat blocks for them list them as vehicles so that we know. But whether or not a vehicle is an object has been debatable on this site for awhile.

The DMG describes objects as :

For the purpose of these rules, an object is a discrete, inanimate item like a window, door, sword, book, table, chair, or stone, not a building or a vehicle that is composed of many other objects.

A vehicle is clearly not a discrete object. It is made up of discrete objects, but a vehicle is much more complicated than that. The descriptions later on about damage thresholds, etc. may apply to vehicles, but that doesn't make them equivalent to things like a castle wall - which is clearly a discrete option.

Some DMs may differ

And that's okay! At times, it may simply be easier to say they're an object. It may result in unintended mechanics, but if it works for your table, then it works for your table.

Based on the prior rule cited above, I do not believe they are discrete objects and would not make complex things like a vehicle active targets as a whole for mechanics that require objects and would not say that an Infernal War Machine (a vehicle) is an object.



Definitely not a creature

Infernal war machines are clearly not spell effects or dungeon hazards. And they are not creatures, although that may be less obvious;

I know it's a vehicle but it's powered by souls and has a stat block like a creature would have.

While 5e does not have a rigorous definition of 'creature' to apply, there are many indications that infernal war machines are not creatures.

The vehicle is powered by souls, but the soul itself is not 'inhabiting' or 'animating' the vehicle. Rather, the soul is burned / consumed in the machine's furnace and supplies nothing more than power or a fuel source. The machine is directed by the driver, and without a driver it will not go anywhere.

BG:DiA tells us (p. 216):

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.

If war machines were creatures, they would not have stat blocks "like those for creatures" - either it would just be assumed that they had stat blocks without mentioning it, or if it was mentioned, it would say "like those for other creatures". The partial stat blocks they have do not list CR or XP, so it is unclear what the PC's would earn by 'defeating' them.

In their stat blocks (ibid):

Infernal war machines usually have a score of O in Intelligence, Wisdom, and Charisma.

Without looking through the entire Monster Manual, the simplest creature I can think of is the shrieker, a magically animated plant whose sole action is to 'shriek' in response to light - it cannot move or attack, or respond in any way to being damaged. Even the lowly shrieker has an Intelligence and Charisma of 1, and a whopping Wisdom of 3 - far above the war machine.

Further, (ibid):

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

Without doing a comprehensive search for creatures, I don't know whether there are any with an ability score of 0, but I do know that if there were, this 'auto fail on saves' is not a rule for creatures. It is, however, similar to the rule for objects (PHB 185):

Objects always fail Strength and Dexterity saving throws, and they are immune to effects that require other saves. When an object drops to 0 hit points, it breaks.

Objects that reach 0 hp break; creatures that do so begin to make death saving throws. Even non-living creatures like undead and constructs are permitted to save against 'death'. Objects don't, however, and neither do war machines (BG:DiA 216):

An infernal war machine's hit points can be restored by making repairs to the vehicle (see "Repairs," page 220). When an infernal war machine drops to 0 hit points, it ceases to function and is damaged beyond repair...

War machines can be repaired, but, unlike creatures, they do not have hit dice and so cannot spend them on short rests to heal themselves.

Objects are immune to poison and psychic damage. Infernal war machines are immune to poison and psychic, as well as fire (presumably since they are made of infernal iron).

Finally, one of the weapons of an example war machine, the Demon Grinder, is a wrecking ball. The wrecking ball does a base 8d8+4 bludgeoning damage, but doubles this damage "if the target is an object or a structure." Structures are pretty scarce in Avernus, and the context of the adventure makes it clear that war machines exist mostly to attack creatures and other war machines; that this weapon would do extra damage to other war machines as objects makes sense, but it does not make sense for it to have this property if the only targets were not war machines but rather the odd object fumbled by the characters, such as a disarmed weapon or dropped Miley Cyrus CD.

But is the machine an object or a collection of objects?

Since war machines are not spell effects, dungeon hazards, or creatures, they are definitely 'object class' entities. But are they objects per se? In defining objects, the DMG says:

For the purpose of these rules, an object is a discrete, inanimate item like a window, door, sword, book, table, chair, or stone, not a building or a vehicle that is composed of many other objects.

Some vehicles, such as carts, are objects. But other vehicles are not objects themselves; rather, they are collections 'composed of many objects'. War machines are vehicles, and given their size and complexity, they certainly seem like candidates for being not objects per se but rather collections of them. Unfortunately, the 5e rules do not explicitly say how many 'other objects' is enough for a vehicle to not be an object itself. Thus, we need to look at the overall context of war machines to decide whether or not they are object themselves.

Unlike war machines, the ships described in Appendix A of [Ghosts of Saltmarsh][15], are explicitly collections of objects:

A ship is composed of different components, each of which comprises multiple objects:
Hull. A ship’s hull is its basic frame, on which the other components are mounted.
Control. A control component is used to steer a ship.
Movement. A movement component is the element of the ship that enables it to move, such as a set of sails or oars, and has a specific speed.
Weapon. A ship capable of being used in combat has one or more weapon components, each of which is operated separately.

Each of these 'components' has its own AC and hp, so that they may be independently targeted during ship-to-ship battles, with specific consequences for destroying one component of a ship while the other components are still functional.

War machines do have 'action stations' which resemble the components of a ship. The smallest war machine (the Devil's Ride) has just a Helm, while the largest (the Demon Grinder) has a Helm, a Chomper, a Wrecking Ball, and two Harpoon Flingers. In addition to these action stations, each infernal war machine has an engine and a furnace, which themselves appear to be 'components composed of multiple objects'.

However, unlike ships, a war machine has a single AC and hp total, meaning that its action stations and other components cannot be individually targeted by damaging effects.

The scalable nature of objects in 5e

One of the consequences of the lack of rigor in the definition of what is an object in 5e is that objects scale to their interaction with the game. By this, I mean that something may be treated as an object when PC's interact with it in one way, but not when they interact with it in another way. For example, if a party was attempting to get through a locked door quickly, the barbarian might attack the door itself, in which case the entire door would be considered an object. But if they were trying to get through the door quietly, then the rogue might work at the lock while the artificer tried to disassemble the hinges. In this case the door would not be an object, but a collection of other objects, and the lock and hinges would be the objects with which the PC's were interacting.

Within this context, the entire war machine should count as one object, for the purposes of effects that cause damage, such as an adamantine sword or a demon grinder's wrecking ball.

On the other hand, spells and other effects that can affect objects without causing damage would more appropriately be targeted at the specific components of the war machine. For example, when casting heat metal on a war machine (and see this question), a caster should have to specifically choose a particular weapon station, or the helm, engine, or furnace. Similarly, the caster of a continual flame spell would need to choose on which component to put the flame.

Infernal war machines are certainly not creatures. They should be 'treated as objects' for the purposes of damaging effects, but as 'vehicles composed of many other objects' for other effects and interactions.


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