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Iron Guardian


AC 20 (natural armor)

HP 210 (20d10 + 100; bloodied 105)

Speed 30 ft.

Proficiency +5; Maneuver DC 20

Damage Immunities fire, poison, psychic; damage from nonmagical, non-adamantine weapons

Condition Immunities charmed , fatigue , frightened , paralyzed , petrified , poisoned

Senses darkvision 120 ft., passive Perception 11

Languages understands the languages of its creator but can’t speak

Fire Absorption. When the guardian is subjected to fire damage, it instead regains hit points equal to the fire damage dealt.

Immutable Form. The guardian is immune to any effect that would alter its form.

Magic Resistance. The guardian has advantage on saving throws against spells and magical effects.

Constructed Nature. Guardians don’t require air, sustenance, or sleep.


Multiattack. The guardian makes two sword attacks.

Sword. Melee Weapon Attack: +12 to hit, reach 10 ft., one target. Hit: 29 (4d10 + 7) slashing damage.

Poison Breath (Recharge 56). The guardian exhales poisonous gas in a 15-foot cone. Each creature in the area makes a DC 18 Constitution saving throw , taking 45 (10d8) poison damage on a failure or half damage on a success.


Deflection. When missed by a ranged attack by a creature the guardian can see, the guardian redirects the attack against a creature within 60 feet that it can see. The original attacker must reroll the attack against the new target.


The iron guardian’s strategy is determined by its programming. It may attack the closest enemy, or it may be instructed to attack only certain targets, such as the first one to touch an item it was protecting. It uses its poison breath whenever it can include two or more creatures in the blast. It uses its Deflection reaction to target either the least-armored creature within range or its preferred target.

Legends and Lore

With an Arcana or Religion check, characters can learn the following:

DC 10 Spellcasters can build guardians, constructs that follow orders mindlessly.

DC 15 All guardians are immune to damage from nonmagical weapons and are resistant to spells. Depending on the material it is made from, a guardian may ignore or even be healed by certain effects. For example, clay guardians are healed by acid; flesh guardians are healed by lightning; and iron guardians are healed by fire. 

DC 20 A damaged guardian may go berserk and no longer function properly.


The iron guardian is one of the strongest and most durable constructs that exists. Explorers have found still-functioning iron guardians dating from the dawn of recorded history. Similar guardians, older still and created by unknown hands, are made of bronze.

Iron guardians can resemble rough humanoid figures, suits of armor, or even monsters such as minotaurs or ettins .


1–2 Guarding an area, attacking trespassers on sight

3 Attacks if trespassers touch or damage certain doors or items

4 Berserk; pacing among broken artwork and furniture, attacking anything that moves

5 Patrolling; stops to fix, clean, repair, or reset items

6 Attacks only to defend itself; clears a path in response to certain actions, such as unlocking a door if you say a certain word, stepping off a concealed trap door if you ask it to move, giving you a key if you beat it at chess, etc.


1 Magic mouth that poses a riddle; the answer deactivates the guardian for 1 minute

2 Several silver necklaces or rings; the guardian ignores creatures that wear this jewelry

3 A bell or gong; ringing it summons the guardian

4 DC 15 Investigation check: a notebook in an ancient language, containing phrases the nearby guardian must obey, such as "attack on sight,” "deactivate." etc.

5 Big round footprints that appear to have walked the same path countless times

6 Distant lumbering footsteps


Guardians stand sentinel over treasure in laboratories, temples, or tombs, or do the bidding of their masters in cities and towns.

CR 5–10 clay , shield , or stone guardian ; 1 or 2 flesh guardians ; flesh guardian with bolt-thrower , gargoyle , or 3 zombies

Treasure 4 rare books (200 gp each), spell scrolls of bestow curse , fear , and remove curse

CR 11–16 iron guardian ; stone colossus ; clay or stone guardian with 1 or 2 basilisks , gelatinous cubes , ochre jellies , or walking statues   

Treasure 5 alexandrite gemstones (500 gp each), portable hole , manual of guardians

CR 17–22 2 clay or stone guardians

Treasure 800 gp, 20 rare books (200 gp each), bead of force , spell scrolls of flesh to stone and forbiddance , 2 maul (black iron, inscribed with the name “Black Key”; the first time each day the maul touches a locked door, it casts knock with spell attack bonus +10)

Monster Type Description

Constructs are beings that were built or made. Some are mindless machines, while others have some form of intelligence. Guardians are constructs.