Gargantuan machine

Armour Class 16 (plating)
Hit Points 242 (132 - 352)
Speed 40 ft., burrow 60 ft.

+8 (C) -2 (D) -2 (D) -2 (D)

Skills notice +6
Damage Resistances fire
Damage Vulnerabilities freeze
Condition Immunities charmed, exhaustion, frightened, paralyzed, poisoned
Senses night vision 60 ft., tremorsense 300 ft., passive notice 16
Challenge 13 (1,800 XP)

Sensitive Tremorsense. The rockbreaker has advantage on perception checks that rely on its tremorsense.

Leaping Crush. If the rockbreaker burrows at least 30 feet straight toward a creature and then hits it with a smash attack on the same turn, that target takes 11 (2d10) additional melee impact damage and must succeed on a DC 20 might saving throw or be knocked prone.

Legendary Resistance (3/day). If the rockbreaker fails a saving throw, it can choose to succeed instead.

From Below. If the rockbreaker burrows at least 30 feet it can emerge from the ground in a space occupied by one or more other creatures. Those creatures are pushed to the nearest available free spaces. If the rockbreaker makes a mouth drills attack against a creatures it has pushed and hits, the target takes the attack's usual damage and is also knocked prone.


Mouth Drills. Melee weapon attack: +12 to hit, reach 10 ft., one target. Hit: 19 (2d10 + 8) melee impact damage.

Smash. Melee weapon attack: +12 to hit, reach 15 ft., one target. Hit: 15 (3d4 + 8) melee impact damage. If the target is a creature, it must succeed on a DC 16 Might saving throw or be knocked prone.

Rock Blast. +12 to hit, range 90 ft., one target. Hit: 15 (3d4 + 8) ranged impact damage.

Legendary Actions

The rockbreaker 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. The rockbreaker regains spent legendary actions at the start of its turn.

Detect. The rockbreaker makes an Acumen (Perception) check.

Attack. The rockbreaker makes a mouth drills or rock blast attack.

Rock Volcano (costs 2 legendary actions). The rockbreaker spits a stream of broken stone upwards, the rocks cascading in a circle around it. All creatures within 15 ft. of the rockbreaker must make a DC 20 Finesse saving throw. On a failed save, a creature takes 15 (3d4 + 8) ranged impact damage and is knocked prone. On a successful save, a creature takes only half damage and isn't prone.


Digging Arm (4)

AC 18; durability 60; damaged by tear.

Tear. When tear damage reduces the digging arm's durability to zero, it is disabled. The rockbreaker's walking speed is reduced by 5 ft. and its burrow speed is reduced by 15 ft.

Fuel Sac (2)

AC 18; durability 80; damaged by tear, impact.

Tear, impact. When damage reduces the fuel sac's durability to zero, it explodes. Every creature within 10 feet must make a DC 15 finesse saving throw or take 21 (6d6) fire damage and suffer the burning condition, taking 6 fire damage for 1d4 turns or until the condition is removed. On a successful save, a creature takes only half damage and isn't burning. The rockbreaker automatically fails its saving throw.

Exhaust Port

AC 20; durability special; damaged by tear, impact.

Damage dealt to the rockbreaker's exhaust port is doubled, then applied to the rockbreaker's hit points.

Rockbreaker Salvage

d20 roll Number of Items
1-9 1
10-15 2
16-19 3
20 4

If a salvage item entry has a maximum, you can only salvage it from any given machine that many times. If you've already reached the limit and roll the same result again, move up the table one step and salvage that item instead. If necessary, continue moving up the table to the next available result for which you haven't already reached capacity.

d% roll Item
1-24 5d10+120 shards
25-42 2d4+4 blaze
43-53 1d2 echo shells
54-61 1 crystal braiding (max 1)
62-67 1 rockbreaker lens (max 2)
68-71 1 large machine core (max 1 )
72-74 1 rockbreaker heart (max 2)
75-100 1 randomly determined weave or coil (max 1).

Roll a random weave or coil from the modification table below. Rare and Very Rare modifications also have a chance of a secondary or even tertiary effect, as explained on the Weaves and Coils pages.

d% roll Modification
1-3 Common Resist Corruption Weave
4-7 Common Resist Fire Weave
8-10 Common Resist Freeze Weave
11-14 Common Resist Melee Damage Weave
15-18 Common Resist Ranged Damage Weave
19-22 Common Resist Shock Weave
23-26 Common Stealth Weave
27-29 Common Corruption Coil
30-33 Common Damage Coil
34-37 Common Fire Coil
38-40 Common Freeze Coil
41-44 Common Handling Coil
45-48 Common Melee Damage Coil
49-52 Common Shock Coil
53-55 Common Tear Coil
56-57 Rare Resist Corruption Weave
58-59 Rare Resist Fire Weave
60-61 Rare Resist Freeze Weave
62-63 Rare Resist Melee Damage Weave
64-65 Rare Resist Ranged Damage Weave
66-67 Rare Resist Shock Weave
68-69 Rare Stealth Weave
70-71 Rare Corruption Coil
72-73 Rare Damage Coil
74-75 Rare Fire Coil
76-77 Rare Freeze Coil
78-79 Rare Handling Coil
80-81 Rare Melee Damage Coil
82-83 Rare Shock Coil
84-85 Rare Tear Coil
86 Very Rare Resist Corruption Weave
87 Very Rare Resist Fire Weave
88 Very Rare Resist Freeze Weave
89 Very Rare Resist Melee Damage Weave
90 Very Rare Resist Ranged Damage Weave
91 Very Rare Resist Shock Weave
92 Very Rare Stealth Weave
93 Very Rare Corruption Coil
94 Very Rare Damage Coil
95 Very Rare Fire Coil
96 Very Rare Freeze Coil
97 Very Rare Handling Coil
98 Very Rare Melee Damage Coil
99 Very Rare Shock Coil
100 Very Rare Tear Coil
Horizon Zero Dawn is the sole intellectual property of Guerilla Games. This is purely a fan work. Rules presented work with D&D 5e. Text and game mechanics presented in this wiki are not Open Game Content and should not be reproduced or repackaged in any way.