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Onyx Scourge

This gigantic creature’s stony body is laced with veins of deep red and black minerals that pulse with dark energy. Its face is a mask of rage with glowing red eyes and a pit of pitch blackness for a mouth.

Onyx Scourge CR 16

XP 76,800
CE Huge outsider (earth, elemental, extraplanar)
Init +6; Senses darkvision 60 ft., see in darkness, tremorsense 60 ft.; Perception +27


AC 30, touch 10, flat-footed 28 (+2 Dex, +20 natural, –2 size)
hp 231 (22d10+110)
Fort +18, Ref +11, Will +15
DR 10/—; Immune death effects, elemental traits, energy drain, negative energy


Speed 30 ft., burrow 20 ft.; earth glide
Melee 2 slams +32 (2d12+12/19–20 plus 3d6 negative energy)
Space 15 ft.; Reach 15 ft.
Special Attacks channel negative energy (8d6, DC 19, 4/day), entropic strikes, negative energy capacitance
Spell-Like Abilities (CL 16th; concentration +17) 3/day—waves of exhaustion (DC 18)


Str 34, Dex 14, Con 21, Int 12, Wis 15, Cha 13
Base Atk +22; CMB +36 (+40 bull rush, +38 sunder); CMD 48 (50 vs. bull rush or sunder)
Feats Awesome Blow, Cleave, Greater Bull Rush, Improved Bull Rush, Improved Critical (slam), Improved Initiative, Improved Sunder, Intimidating Prowess, Lightning Reflexes, Power Attack, Sundering Strike
Skills Appraise +26, Climb +37, Intimidate +38, Knowledge (dungeoneering, planes) +26, Perception +27, Stealth +19
Languages Terran


Channel Negative Energy (Su)

As a standard action, an onyx scourge can channel negative energy in a 30-foot burst as a 16th-level evil cleric. This ability requires no divine focus.

The save DC is Charisma-based.

Entropic Strikes (Ex)

An onyx scourge’s slam attack deals an additional 3d6 points of negative energy damage. When used against an object, its slam attack ignores the first 5 points of hardness.

Negative Energy Capacitance (Su)

An onyx scourge’s body stores negative energy, making it immune to death effects, energy drain, and negative energy. Additionally, if an onyx scourge is targeted by a negative energy attack, the next time it channels negative energy within 1 minute, it deals 50% more damage, as though this were an empowered spell.


Environment any underground (Plane of Earth)
Organization solitary or pair
Treasure incidental

Onyx scourges are vicious brutes from the Plane of Earth that revel in their deadly power. They resemble elder earth elementals with striations of red and black onyx. Negative energy pulses and flows through the streaks of onyx like blood through exposed veins. The hollows and depressions that serve as an onyx scourge’s eyes and mouth are deep voids warped into expressions of rage and hatred.

Negative energy flows through each strike an onyx scourge makes, disrupting living and unliving matter alike. Onyx scourges can also unleash this energy in a devastating blast, which they enjoy using to inflict damage on multiple opponents at once. They gleefully wade into battle whenever given the opportunity.

An onyx scourge is 40 feet tall and weighs 70,000 pounds.


The endless tunnels on the Plane of Earth are home to wondrous creatures. Elementals dwelling there are formed from the plane’s very substance, displaying limitless variations in combinations of different ores, minerals, and materials. In most cases, elementals gain no special benefit from their constituent minerals other than distinctive coloration. In rare situations, however, an elemental encounters a phenomenon that interacts with its physical makeup in strange and terrible ways.

Legends circulated among the shaitan posit that one such occurrence gave rise to the first onyx scourges.

Shaitan tales say that, in the distant past, an elder earth elemental discovered a strange anomaly: a sphere of black onyx the size of a small mountain exuding wisps of chill, dark power. Curious about the object’s nature, the elder elemental entered the sphere to explore its interior, but discovered too late that the onyx sphere surrounded a breach between the Plane of Earth and the Negative Energy Plane.

Planar scholars theorize that the onyx sphere formed around the breach as a defense mechanism, to contain the destructive power of the Negative Energy Plane. The elder elemental should have been annihilated by its exposure to the negative energy of the breach, but its body absorbed the onyx to likewise contain the negative energy. The elemental survived the ordeal but emerged from the sphere radically changed—a twisted elemental creature infused with the essence of entropy and filled with the desire to destroy.

The elemental gathered other elementals through coercion, trickery, or promises of power, and then forced them to enter the onyx sphere just as it had done. Only the most powerful elementals survived, similarly transformed into creatures like the elemental. Infused with destructive energy and feeling no loyalty to each other nor to the elder elemental, these creatures spread ruin across the Plane of Earth and eventually into other planes. They came to be called onyx scourges, after the pulsing energy in their onyx striations and the devastation they leave in their wake.

No shaitan claims to know how many onyx scourges exist, or if they were all created by the elder elemental. Explorers have never found the elder elemental’s planar breach on the Plane of Earth or even definitive proof that the elder elemental existed at all. It is possible that more than one breach exists, each with the ability to create onyx scourges from elementals that venture too close yet are powerful enough to survive the exposure.

Tracing the origin of onyx scourges is difficult for several reasons. First, onyx scourges are truculent, prone to answering questions with lies if they deign to answer them at all. Second, the creatures are by nature powerful and incredibly destructive; they generally attack any creatures in their path and are disinclined to leave survivors. Finally, the creatures constantly wander until they find a territory to call their own and so are likely encountered far from whatever their point of origin might have been.

Habitat and Society

Onyx scourges are most often found on the Plane of Earth. They are generally solitary creatures that lay claim to a certain region of the plane— usually several miles wide—and viciously attack elementals and other denizens of that region.

After dwelling in one area for a time, a scourge moves to a new area and wages war on whatever creatures happen to reside in its new chosen territory. If a scourge’s domain encompasses a major trade route on the Plane of Earth, shaitan merchants soon dispatch agents to destroy or relocate the creature.

Although some scholars dispute the details of the story of the elder elemental, others believe there is a grain of truth within the tale and seek the fabled onyx sphere.

Necromancers desire the negatively charged onyx to enhance their vile experiments or to create powerful new undead monsters and constructs. Forbidden tomes theorize that the black onyx can be used to unlock greater powers from the legendary Shadowstaff and other necromantic artifacts. The promise of such power has led many wizards to spend their fortunes and their lives to find the elder elemental’s domain.

Onyx scourges on the Plane of Earth make terrifying predators. Although their primary motive is to wage war against all creatures in the territories they have claimed as their own, onyx scourges sometimes venture into other earth elementals’ territories to capture prey, which is very rarely seen again.

On the Material Plane, onyx scourges present an even greater danger to mortals. Their destructive power is compounded by their ability to bolster nearby undead, creating devastating juggernauts that would be prized weapons in a necromancer’s army. Onyx scourges can heal undead forces while annihilating living troops and their defensive fortifications. Thankfully, only the most powerful spellcasters can bring an onyx scourge through a gate, and the creatures are too strong to be magically controlled by normal means. That doesn’t stop ambitious spellcasters from making the attempt, and the cleverest of them might even use the onyx scourges’ love of destruction to convince one to join a campaign.

Section 15: Copyright Notice

Pathfinder Adventure Path #120: Vault of the Onyx Citadel © 2017, Paizo Inc.; Authors: Larry Wilhelm, with Paris Crenshaw, Crystal Frasier, Tim Hitchcock, Kalervo Oikarinen, and Greg A. Vaughan.