Regular Orthoclath

Large Construct, Lawful Neutral

AC: 20

Initiative: -1 (9)

HP: 210 (20d10 + 100)

Speed: 30 ft.

STR: 24 (+7)
DEX: 9 (-1)
CON: 20 (+5)
INT: 16 (+3)
WIS: 16 (+3)
CHA: 16 (+3)

Immunities: fire; poison; psychic; bludgeoning, piercing, slashing from nonmagical attacks that aren't adamantine

Condition Immunities: charmed; exhaustion; frightened; paralyzed; petrified; poisoned

Senses: darkvision 120 ft., Passive Perception 10

Languages: understands the languages of its creator but can't speak

CR: 16 (XP 15,000; PB +5)

Fire Absorption.

Whenever the orthoclath is subjected to fire damage, it takes no damage and instead regains a number of hit points equal to the fire damage dealt.

Immutable Form.

The orthoclath is immune to any spell or effect that would alter its form.

Magic Resistance.

The orthoclath has advantage on saving throws against spells and other magical effects.

Magic Weapons.

The orthoclath's weapon attacks are magical.

Actions

Multiattack.

The orthoclath makes two melee attacks.

Slam.

Melee Weapon Attack: +13 to hit, reach 5 ft., one target. Hit: 20 (3d8 + 7) bludgeoning damage.

Sword.

Melee Weapon Attack: +13 to hit, reach 10 ft., one target. Hit: 23 (3d10 + 7) slashing damage.

Poison Breath (Recharge 5-6).

The orthoclath exhales poisonous gas in a 15-foot cone. Each creature in that area must make a DC 19 Constitution saving throw, taking 45 (10d8) poison damage on a failed save, or half as much damage on a successful one.

Find this creature in the encounter builder

Source: Chains of Asmodeus, p. 171 - Licenses and attribution