The Iron Knight is a mechanical vehicle in a humanoid shape that usually requires a crew of four to operate. It is Gargantuan, though smaller than most of the kaiju it is meant to face. It stands 42 feet high and occupies a 20-ft. square. Combat in the Iron Knight requires a different kind of teamwork than ordinary battles, and the statistics and features of each crew member greatly affect the Iron Knight’s potency.
Unique Gargantuan mech (land vehicle)
|23 (+6)||14 (+2)||20 (+5)||10 (+0)||10 (+0)||10 (+0)|
Saving Throws (without an Engineer) by ability score, no proficient saves (with an Engineer) use Engineer’s proficient saving throws and proficiency bonus
Skills Athletics and Acrobatics use the Iron Knight’s ability scores and the Driver’s proficiency bonus, including Expertise if any
Damage Resistances necrotic, radiant
Damage Immunities poison, psychic
Condition Immunities blinded, charmed, deafened, frightened, paralyzed, petrified, poisoned, stunned, unconscious
Senses none intrinsic; use the Commander’s senses unless other crew members open portholes
Challenge 20 (25,000 XP)
- Crewed Mech. The four crew positions in the Iron Knight are the Commander, the Gunner, the Driver, and the Engineer. Each can act only once per round. One crew member acts on the Iron Knight’s initiative (determined by group consensus), while the other three act on the Iron Knight’s legendary actions. No crew member can act more than once in a round. The features of each crew position are described below as well. While their portholes are closed, crew members have total cover and are completely encased in the Iron Knight. The Iron Knight can be made watertight and airtight for up to ten minutes at a time; past that, the crew begins to suffocate. A crew member at a battle station can communicate with other crew members, but cannot easily be reached from another station; doing so requires 1d4 rounds of actions. The stations accommodate Small or Medium creatures, but no larger. If the Iron Knight has 0 hit points, the Iron Knight falls to the ground, dealing 7 (2d6) bludgeoning damage to all crew and passengers. The hatches to the crew compartments and the passenger compartments automatically open, and in most possible positions for the Iron Knight to fall, the crew and passengers can exit safely. Any crew member can issue a command for the Iron Knight to move up to its speed over clear terrain on its turn. Only the Driver can issue a command for the Iron Knight to perform more complicated movement, such as jumping, climbing, or navigating difficult terrain. It ignores normal difficult terrain, though, and treats thick forests, settlements, or mountains as difficult rather than impassable terrain.
- Siege Monster. The Iron Knight deals double damage to objects and structures.
- Passengers. The Iron Knight can carry up to 6 Medium passengers, or an equivalent volume of cargo or passengers of other sizes. Passengers cannot participate in combat, and cannot directly reach crew members without first exiting the Iron Knight.
- Semi-Living. A mending spell targeting the Iron Knight restores 1d6 hit points to it. Magical healing spells, such as cure wounds, instead grant the Iron Knight half the amount they would restore as temporary hit points, which fade after 10 minutes. Other kinds of healing effects, from potions of healing to the Life domain’s Channel Divinity: Preserve Life feature, do not affect the Iron Knight.
- Ammunition. The Iron Knight holds 30 cannonballs. As part of a short or long rest, it can process raw or scrap metal into new cannonballs, requiring 24 lb. of metal per cannonball. It can restock up to 10 cannonballs in the span of a short rest, or up to 30 in the span of a long rest.
- Multiattack. The Iron Knight makes a number of longsword, cannon, or slam attacks, in any combination. The number of attacks is determined by the activating crew member’s Extra Attack feature, if any. If the activating crewmember has the Multiattack feature that allows it to use multiple attacks with manufactured weapons, it can use its Multiattack action using the Iron Knight’s melee and ranged attacks.
- Longsword. Melee Weapon Attack: Gunner’s proficiency bonus + 6 to hit, reach 20 ft., one target. Hit: 24 (4d8 + 6) slashing damage.
- Cannon. Ranged Weapon Attack: Gunner’s proficiency bonus + 5 to hit, range 100/600 ft., one target. Hit: 20 (4d6 + 6) piercing damage.
- Slam. Melee Weapon Attack: Activating crew member’s proficiency bonus + 6 to hit, reach 20 ft., one target. Hit: 20 (4d6 + 6) bludgeoning damage, and the target must make a DC 17 Strength saving throw. On a failed save, it is pushed 20 feet and knocked prone.
The Iron Knight can take 3 legendary actions, choosing from the options below. Only one legendary action can be used at a time and only at the end of another creature’s turn. Each crew member can command only one action (normal or legendary) in each round, but crew members’ commands are not constrained by their own initiative.
- Longsword. The Iron Knight makes one longsword attack. Once it uses this ability, it cannot do so again until the end of its next turn. If the activating crew member is the Gunner, it scores a critical hit on a roll of 19 or 20.
- Cannon. The Iron Knight makes one cannon attack. Once it uses this ability, it cannot do so again until the end of its next turn. If the activating crew member is the Gunner, it scores a critical hit on a roll of 19 or 20.
- Slam. The Iron Knight makes one slam attack. Once it uses this ability, it cannot do so again until the end of its next turn. If the activating crew member is the Gunner, it scores a critical hit on a roll of 19 or 20.
- Repair (Engineer or Commander only). The Iron Knight regains 5d8 hit points. Once it uses this ability, it cannot do so again until the end of its next turn.
- Bolster (Engineer only). The Engineer adds their proficiency bonus to one of the Iron Knight’s saving throws, skills, or the damage of its longsword, cannon, or slam attack. This effect lasts until the Engineer loses Concentration or leaves the battle station.
- Dodge (Driver or Commander only). The Iron Knight uses the Dodge action. All attacks against the Iron Knight have disadvantage until the end of the Iron Knight’s next turn.
- Open a Porthole (Driver, Engineer, or Gunner only). The crew member opens their porthole. They gain three-quarters cover rather than total cover, but can see targets outside the Iron Knight. The Iron Knight is not watertight or airtight while any porthole is open.
- Close a Porthole (Driver, Engineer, or Gunner only). The crew member closes their porthole. They gain total cover, and can’t see targets outside the Iron Knight.
- Cast a Spell. The crew member casts a spell. The Commander can always target creatures or objects outside the Iron Knight; other crew members must have an open porthole to target anything other than crew members, passengers, or the Iron Knight.
- Move. The Iron Knight moves up to its speed. Only the Driver can command the Iron Knight to cross difficult terrain, stand up from prone, or perform more complex movement such as jumping or climbing.
Larger Or Smaller Groups
To adjust the Iron Knight for groups larger than four characters, add the following trait.
Arcane Resonance. Each of the Iron Knight’s battle stations builds up its own unique resonance as a person issues commands. The first hour at a battle station is within tolerances for all player races. Every half-hour, or portion thereof, afterward that a creature works at a particular battle station, they suffer one level of exhaustion. Arcane resonance for a particular battle station leaves a creature’s system once it completes a long rest. Working a different battle station creates a different arcane resonance effect. For groups smaller than four, the order of priority for crewing battle stations is Gunner, Driver, Engineer, and finally Commander.