Sentinel Colossus

Large construct, unaligned

Armor Class 19 (adamantine plating)
Hit Points 252 (24d10 + 120)
Speed 40 ft.

22 (+6) 12 (+1) 20 (+5) 10 (+0) 14 (+2) 6 (-2)

Saving Throws Str +10, Con +9
Damage Resistances bludgeoning, piercing, and slashing from nonmagical attacks
Damage Immunities poison, psychic
Condition Immunities charmed, exhaustion, frightened, paralyzed, poisoned
Senses darkvision 60 ft., passive Perception 15
Languages understands the languages of its creator but can’t speak
Challenge 12 (8,400 XP)


  • Immutable Form. The sentinel construct is immune to any spell or effect that would alter its form.


  • Multiattack. The sentinel colossus makes three slam attacks.
  • Slam. Melee Weapon Attack: +10 to hit, reach 10 ft., one target. Hit: 28 (5d8 + 6) bludgeoning damage.
  • Shield of Force (Recharge 5-6). The sentinel colossus activates a protective shield of force around itself. Until the start of its next turn, the construct gains a +4 bonus to its AC and resistance to all damage. Additionally, any creature that hits the construct with a melee attack takes 18 (4d8) force damage.
  • Explosive Blast (Recharge 5-6). The sentinel colossus releases a burst of explosive energy in a 30-foot cone. Each creature in that area must make a DC 17 Dexterity saving throw, taking 36 (10d12) force damage on a failed save, or half as much damage on a successful one.
  • Siege Slam. The sentinel colossus raises its mighty fists and slams them into the ground, causing tremors in a 20-foot radius. Each creature within that area must make a DC 17 Dexterity saving throw, taking 65 (4d10 + 6) bludgeoning damage and being knocked prone on a failed save, or half as much damage and not being knocked prone on a successful one. Additionally, the ground becomes difficult terrain for 1 minute after this action is used.


The sentinel colossus can take 3 legendary actions, choosing from the options below. Only one legendary action option can be used at a time, and only at the end of another creature’s turn. The sentinel colossus regains spent legendary actions at the start of its turn.

  • Slam. The sentinel colossus makes one slam attack.
  • Shielding Aura (Costs 2 Actions). The sentinel colossus emits a protective aura in a 20-foot radius. Until the start of its next turn, all creatures of the construct’s choice within the aura gain a +2 bonus to their AC and resistance to all damage.


The Sentinel Construct is unusual for a construct due to its ability to think and reason. It possesses an intelligence that is neither remarkable nor inferior. Despite this, it has an unwavering loyalty to its creator, even after their demise. However, it lacks the emotion that could cause it to become duplicitous to those around it or disloyal to its creator.

Reasoning Servant. The creation of a Sentinel Construct demands greater magical resources compared to lesser animated creatures. However, once it is infused with magical life, the Sentinel Construct operates with minimal direction, diligently executing its assigned duties. It is able to understand its creator’s intent rather than rigidly adhering to the exact letter of their instructions.

Skilled Combatants. In combat, the Sentinel Construct employs the tactical cunning of a seasoned warrior, prioritizing attacks on foes who are less capable in melee combat while possessing greater potential to harm from a distance. While it demonstrates a strategic approach to engagement, its intelligence does not extend to actions it could take to modify its surroundings or actively improve its defensive position.

Section 15: Copyright Notice

Constructs & Clockworks (5E) © 2023, Darrin Drader Designs; Author Darrin Drader

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