Large construct, neutral

19 (+4) 11 (+0) 18 (+4) 13 (+1) 14 (+2) 6 (-2)

Armor Class 16 (natural armor)
Hit Points 76 (8d10 + 32)
Speed 40 ft.
Saving Throws Constitution +7, Wisdom +5
Damage Immunities fire, poison, psychic; bludgeoning, piercing, and slashing from nonmagical weapons that aren’t adamantine
Condition Immunities charmed, exhaustion, frightened, paralyzed, petrified, poisoned
Senses darkvision 60 ft., passive Perception 12
Languages speaks the languages of its creator
Challenge 7 (2,900 XP)

Special Traits

  • Improved Critical. The thunderbones’ claws score a critical hit on a roll of 19 or 20.
  • Immutable Form. The thunderbones is immune to any spell or effect that would alter its form.
  • Magic Resistance. The thunderbones has advantage on saving throws against spells and other magical effects.
  • Magic Weapons. The thunderbones’ claw attacks are magical.


  • Multiattack. The thunderbones makes three claw attacks.
  • Claw. Melee Weapon Attack: +7 to hit, reach 10 ft., one target. Hit: 14 (3d6 + 4) slashing damage, plus 3 (1d6) lightning damage.


Thunderbones are relentless and unimaginative in their approach to combat. They will chose as many targets as they can easily reach and attack all of them. If their foes are canny and retreat in various directions, the thunderbones will choose one of them, seeming at random, to focus upon. Almost all of the original creations have the lightning damage feature to their claws, but some recent creators have innovated and substituted in another damage type, such as fire, cold or even thunder.


The creature looks like a large humanoid skeleton made entirely of black iron. The bones are covered with small silver runes, each painstakingly etched. These impressive constructs are a relatively new creation.

Thunderbones have been appearing more and more recently in the homes and workshops of the youngest generation of accomplished spellcasters. Although the ritual involved in their creation is complex, the relative cost is low compared to that of most other constructs, and the concept itself is simple: transform a large animated skeleton into a construct of animated iron, and bestow magical abilities upon its bladed claws.

Thunderbones are implacable and utterly loyal, obeying only their creator. Once set in motion, they pursue their goals relentlessly unless their creator is on hand to prevent excessive violence, or unless their instructions explicitly limit their actions. This last can be rather tedious and difficult, for thunderbones’ relative inexpensiveness and ease of construction has a few drawbacks – it can normally only understand a single command in the form of a straightforward sentence no more than a dozen words in length, such as “Defend me against all who assault me” or “Slay all who enter here, but don’t harm me or my wife.”

Section 15: Copyright Notice

Creature Collection 5e Copyright 2020 Onyx Path Publishing, Inc.