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Great Old One

Source Bestiary 4 pg. 135
The Great Old Ones are otherworldly entities of almost unimaginable power—beings completely alien to humanity, both physiologically and spiritually. They exist in the forgotten corners of distant worlds or lost dimensions, yet their power is so great they can inf luence certain sensitive mortal minds in their dreams and nightmares, even if such inf luence is as accidental as a star’s gravitational pull on a tiny mote of dust adrift in space. In such ways, cults devoted to the Great Old Ones can rise on worlds throughout the Material Plane, even without prior contact between these worlds. Some of the Great Old Ones grant access to the domain of Void and its associated subdomains (see below).

While not all of the Great Old Ones are evil, all are forces of chaos. Their cults are almost always evil and cause harm and madness, but the Great Old Ones are generally content to ignore lesser life such as humans, elves, and dwarves. Yet when their attention is garnered, the results can be catastrophic on an immense scale— for just as the ant who bites someone’s toe invites swift destruction on a scale its feeble mind can’t envision, so too does humanity invite unimaginable ruin by delving into the affairs of these powerful creatures.

The Great Old Ones themselves often serve and worship even greater powers, such as Azathoth, Nyarlathotep, Shub-Niggurath, and Yog-Sothoth. Those creatures are the Outer Gods, and whereas the Great Old Ones can be thought of as akin to demigods, the Outer Gods are themselves true deities.

Other Great Old Ones

Bokrug, Cthulhu, and Hastur are but three of the Great Old Ones—countless others exist on distant worlds or other dimensions, yet are still able to influence the world through their dreams and cults. The central concept of the Great Old Ones was created by H. P. Lovecraft, one of the most influential writers of weird fiction—and horror fiction in general—of the 20th century. Lovecraft actively encouraged his writer friends to add to his mythos of creatures, and today we have Great Old Ones created not only by Lovecraft’s contemporaries like Clark Ashton Smith, Robert E. Howard, Henry Kuttner, and August Derleth, but also by modern writers like Ramsey Campbell, Brian Lumley, and Stephen King. Chaosium’s excellent Call of Cthulhu roleplaying game is a perfect place to start delving into the realm of Great Old Ones evoked in RPG form. By creating new Great Old Ones for your game, you can become part of a tradition of shared mythology nearly a century old!

Creatures in "Great Old One" Category

Tawil At'umr30

Great Old One, Mhar

Eight pairs of crystalline legs support this enormous volcano. The volcano’s crater constantly spews smoke and roiling lava.

Mhar CR 26

Source Pathfinder #138: Rise of New Thassilon pg. 86
XP 2,457,600
CE Colossal aberration (chaotic, evil, Great Old One)
Init +15; Senses blindsight 120 ft., darkvision 60 ft., tremorsense 600 ft.; Perception +45
Aura cloak of ash (30 ft.), unspeakable presence (300 ft., DC 35)


AC 43, touch 13, flat-footed 42 (+1 Dex, +10 insight, +30 natural, –8 size)
hp 592 (32d8+448); regeneration 20 (electricity, see below)
Fort +24, Ref +13, Will +28
Defensive Abilities earthen regeneration, insanity (DC 35); DR 15/epic and good; Immune ability damage, ability drain, aging, cold, death effects, disease, energy drain, fire, mind-affecting effects, paralysis, petrification, plane shift; Resist acid 30, electricity 30, sonic 10; SR 37


Speed 40 ft., burrow 120 ft.
Melee 4 claws +33 (4d12+16/19–20 plus 2d6 fire)
Space 50 ft., Reach 50 ft.
Special Attacks mythic power (10/day, surge +1d12), taphophobic dreams, volcanic tempest
Spell-Like Abilities (CL 32nd; concentration +41)
At will—dimension doorM, dreamM, greater dispel magic, insanity (DC 26), mindwipe (DC 23), nightmareM (DC 24), synesthesia (DC 22), wall of fire, wall of stone
3/day—demand (DC 27), earthquake (DC 27), quickened feeblemind (DC 24)
1/day—meteor swarm (DC 28), microcosm (DC 28), symbol of insanity (DC 27)


Str 42, Dex 13, Con 38, Int 28, Wis 31, Cha 29
Base Atk +24; CMB +48 (+52 bull rush); CMD 69 (71 vs. bull rush, can't be tripped)
Feats Awesome Blow, Combat Reflexes, Critical Focus, Greater Bull Rush, Greater Vital Strike, Improved Bull Rush, Improved Critical (claw), Improved Initiative, Improved Lightning Reflexes, Improved Vital Strike, Lightning Reflexes, Power Attack, Quicken Spell-Like Ability (feeblemind), Stunning Critical, Vital Strike, Weapon Focus (claw)
Skills Climb +51, Intimidate +44, Knowledge (arcana, geography, history, local, nature, planes) +41, Perception +45, Sense Motive +42, Stealth +20, Survival +45, Swim +51
Languages Aklo, Ignan, Terran; telepathy (100 ft.)
SQ massive, otherworldly insight


Environment any land
Organization solitary (unique)
Treasure double

Special Abilities

Cloak of Ash (Ex) A blanketing layer of swirling ash surrounds Mhar’s bulk, obscuring the vision of anyone who draws too close. All creatures within the area have concealment. A strong wind (21+ mph) disperses the ash after 1 round. The ash returns immediately once the strong wind ends.

Earthen Regeneration (Ex) Mhar’s regeneration functions only while it is burrowing, submerged in lava, or otherwise underground. The regeneration continues for 1 minute after it emerges aboveground. If Mhar’s regeneration is stopped, the regeneration automatically resumes when Mhar burrows or enters lava.

Immortality (Ex) If Mhar is slain, it explodes violently, spraying earth and lava in all directions. Creatures within 30 feet of Mhar take 30d6 points of bludgeoning damage and 30d6 points of fire damage. A creature can attempt a DC 40 Reflex save for half damage. Mhar manifests again 1 year later in the same area, restored to life via true resurrection.

Massive (Ex) Due to Mhar’s tremendous size, it treats uneven ground and other terrain features that form difficult terrain as normal terrain, though areas of forest or significant settlements are still considered difficult terrain to Mhar. A Huge or smaller creature can move through any square occupied by Mhar, and vice versa. Mhar can make attacks of opportunity only against foes that are Huge or larger, and can be flanked only by Huge or larger foes. Mhar gains a bonus for being on higher ground only if its entire space is on higher ground than that of its target. It’s possible for a Huge or smaller creature to climb Mhar—this generally requires a successful DC 30 Climb check, and unlike the normal rules regarding Mhar and attacks of opportunity, a Small or larger creature that climbs on its body provokes an attack of opportunity from Mhar. Any creature that climbs on Mhar is treated as if it is totally immersed in lava.

Taphophobic Dreams (Su) When Mhar uses its nightmare spell-like ability on a creature within 5 feet of earth or worked stone, it also afflicts that creature with terrifying dreams of an immense presence surging through the ground, ominously circling the target and threatening to pull it under. In addition to the effects of nightmare, the target must also succeed at a DC 35 Will save or be unwilling to approach within 5 feet of any amount of earth or stone and, if within such an area, compelled to leave it immediately. The creature is profoundly uncomfortable in such an area, reducing its Dexterity score to 1. This is a mind-affecting curse effect. The save DC is Charisma-based.

Unspeakable Presence (Su) Failing a DC 35 Will save against Mhar’s unspeakable presence causes the victim to experience the crushing entombment of earth and lose the ability to breathe as long as it remains within the area of effect. The save DC is Charisma-based.

Volcanic Tempest (Ex) Once every 1d6 rounds, Mhar can spew a torrential rain of lava, fire, and caustic ash as a full-round action. All creatures within 60 feet of Mhar take 8d6 points of bludgeoning damage and 8d6 points of fire damage (DC 40 Reflex half). In addition, the ground within 60 feet of Mhar when it uses this ability becomes covered in a thin layer of lava. Any creature that ends its turn within this lava takes 20d6 points of fire damage. The lava cools after 1 minute. Finally, the area within 60 feet of Mhar when it uses this ability fills with deadly ash that functions as stinking cloud (Fortitude DC 40 negates). This ash disperses naturally after 1 minute. The save DCs are Constitution-based.


Mhar is a Great Old One that was born eons ago on the edge of the Material Plane. A unique planar rift caused pure essence from the Plane of Earth and Plane of Fire to collide and fuse together, coalescing into a being that lived in a state of constant anguish—a mass of volcanic eruptions that cooled and melted away in a cycle that caused it unending pain. Seeking relief from its torment but unable to escape the Material Plane, Mhar alleviated its suffering by traveling the stars.

Mhar found nascent planets that were still made of roiling magma. For a time, Mhar could rest in the core of these planets, but even such primordial heat could not keep Mhar sedated. Mhar would eventually awaken, destroying the planet and departing to find another haven elsewhere. After destroying countless worlds, Mhar learned a way to escape to the Elemental Plane of Fire. Unfortunately for Mhar, this required greater power than it currently had. Mhar found another young planet—the world called Golarion—burrowed deep into its core, and waited to grow.

While Mhar rested, the goddess Sarenrae tore open a portion of the Material Plane to seal Rovagug within the Dead Vault. Unbeknownst to her, she slew Mhar in that process, granting it the reprieve from pain it had always sought. However, even oblivion could not quell Mhar’s suffering, and its agony was enough to stir it from death. When Mhar awakened yet again, trapped within the crust of Golarion, it went mad, unable to escape its own torment. Mhar let out a psychic scream. As this scream rebounded and echoed between the crust and Mhar itself, intensifying the creature’s madness, the mental force of it pushed against the surface of the earth and formed the Kodar Mountains.

Mhar seeks to break free from beneath Golarion’s crust and destroy the world, then use the magma as a focus to open a breach to the Plane of Fire and flood the entire Material Plane with lava. Once all of reality is a mass of fire and destruction, Mhar can finally find peace.