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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, Mordiggian

This massive wormlike creature appears to be made of solid darkness that sucks surrounding light into its body to be forever extinguished.

Mordiggian CR 30

Source Pathfinder #110: The Thrushmoor Terror pg. 86
XP 9,830,400
CE Gargantuan aberration (chaotic, evil, Great Old One, incorporeal)
Init +31; Senses all-around vision, darkvision 60 ft., see in darkness, true seeing; Perception +50
Aura unspeakable presence (300 ft., DC 40)


AC 47, touch 47, flat-footed 31 (+13 deflection, +15 Dex, +1 dodge, +12 insight, –4 size)
hp 752 (35d8+595); fast healing 30
Fort +28, Ref +26, Will +31
Defensive Abilities absorb light, immortality, incorporeal, insanity (DC 40); DR 20/epic and lawful; Immune ability damage, ability drain, acid, aging, blindness, cold, death effects, disease, energy drain, mind-affecting effects, paralysis, and petrification; Resist electricity 30, fire 30; SR 41


Speed fly 60 ft. (perfect)
Melee 6 +5 tentacles +43 (5d6+18/19–20 plus grab)
Space 20 ft., Reach 20 ft. (40 ft. with tentacle)
Special Attacks constrict (5d6+13), dreams of darkness, engulf (DC 27, 20d6 negative energy and 1d4 negative levels), mythic power (10/day, surge +1d12), tentacles
Spell-Like Abilities (CL 30th; concentration +43)
Constant—speak with dead (DC 26), true seeing
At will—astral projection, create undead, death knellM (DC 25), deeper darkness, dreamM, greater dispel magic, greater teleport, nightmareM (DC 28), sendingM
3/day—demand (DC 31), quickened deeper darkness, energy drain (DC 32), quickened feeblemind (DC 28), quickened slay living (DC 30)
1/day—destruction (DC 30), power word killM, symbol of death (DC 31), symbol of insanity (DC 31), true resurrection


Str —, Dex 40, Con 44, Int 33, Wis 34, Cha 37
Base Atk +26; CMB +45 (+49 disarm); CMD 81 (83 vs. disarm)
Feats Ability Focus (slay living), Blinding Critical, Combat Expertise, Combat Reflexes, Critical Focus, Dodge, Greater Disarm, Greater Vital Strike, Improved Critical (tentacle), Improved Disarm, Improved Initiative, Improved Vital Strike, Mobility, Quicken Spell-Like Ability (deeper darkness, feeblemind, slay living), Vital Strike, Weapon Focus (tentacle)
Skills Acrobatics +53, Bluff +48, Diplomacy +48, Fly +55, Knowledge (arcana) +46, Knowledge (geography) +46, Knowledge (history) +46, Knowledge (local) +46, Knowledge (nobility) +46, Knowledge (religion) +49, Perception +50, Sense Motive +47, Spellcraft +49, Stealth +41, Use Magic Device +48
Languages Aklo, Necril, speak with dead; telepathy 300 ft.
SQ no breath


Environment any
Organization solitary (unique)
Treasure triple

Special Abilities

Absorb Light (Su) Mordiggian’s presence causes all light levels within a 100-foot spread to be reduced by one category as long as he has at least 1 hit point. Anyone who attempts to cast a spell with the light descriptor in this area must succeed at a DC 30 caster level check, or the spell is lost as if it had been counterspelled.

Dreams of Darkness (Ex) Mordiggian can affect a creature that has been restored to life by a worshiper of Mordiggian, that has suffered negative energy damage while within the walls of a temple devoted to Mordiggian, or that has been in the area of effect of Mordiggian’s unspeakable presence (whether or not the creature was affected by it) with dreams of darkness. When Mordiggian uses his nightmare spell-like ability on such a target, the victim endures what seems to be the passage of hundreds of years imprisoned in a lightless sarcophagus or coffin. Upon waking, the creature takes an additional effect beyond the normal effects of nightmare—it must succeed at a DC 40 Fortitude saving throw or contract an accelerated form of ghoul fever that inflicts its damage every hour instead of every day. This is a death effect. The save DC is Charisma-based.

Eldritch Insight (Ex) The whispers of all the world’s dead echo in Mordiggian’s mind, and as a result, he adds his Wisdom modifier as an insight bonus to his Armor Class and on all Initiative checks. If Mordiggian is on a planet or in a dimension where no creature has ever died, this ability does not function.

Engulf (Su) When Mordiggian engulfs a creature, he inflicts 20d6 points of negative energy damage and 1d4 negative levels. A successful DC 44 Reflex saving throw halves the negative energy damage, and a DC 44 Fortitude save removes the negative levels. The save DCs are both Constitution-based.

Great Old One Traits Rules for Mordiggian’s Great Old One traits such as immortality, insanity, and otherworldly, as well as the rules for his mythic abilities and unspeakable presence can be found on page 306 of Pathfinder RPG Bestiary 4.

Immortality (Ex) If Mordiggian is killed, the shadows that comprise his body lose all form and become a 20-foot-diameter roiling blot of churning darkness with a 300-foot fly speed and perfect maneuverability. This blot of darkness is incorporeal and cannot be harmed, but it cannot enter an area of bright light. The blot can sense all undead creatures within a 100-mile radius, and if it finds an undead creature, it can attempt to infuse it. An intelligent undead can resist this attack with a successful DC 40 Will saving throw; unintelligent undead receive no save. Once this blot of darkness infuses an undead creature, it grants the undead creature the advanced creature simple template, but 24 hours later, the undead is destroyed, releasing a fully-healed Mordiggian back into the world. If Mordiggian cannot find a suitable undead host within 24 hours or is trapped by bright light for that duration, the blot of darkness fades away, only to manifest immediately on another world—perhaps in the distant past, in the distant future, or even in the present. The save DC is Charisma-based.

Tentacles (Su) Mordiggian’s tentacles are primary attacks that inflict bludgeoning damage. He adds his Charisma modifier to damage done by his tentacles, which also gain a +5 enhancement bonus on attack rolls and damage rolls. These tentacles are treated as magic epic chaotic weapons for the purpose of overcoming damage reduction. If Mordiggian reduces a living creature to fewer than 0 hit points with a tentacle or with his constriction damage, he automatically casts death knell on the target as a free action.

Unspeakable Presence (Su) Failing a DC 40 Will saving throw against Mordiggian’s unspeakable presence causes the victim to become permanently blinded. A creature that is killed while blinded by this ability immediately animates as a chaotic evil juju zombie (Pathfinder RPG Bestiary 2 291). The save DC is Charisma-based.


Called the Charnel God by his worshipers, Mordiggian is one of the oldest and most powerful of the Great Old Ones. However, his tendency to move back and forth in time whenever he reincarnates makes the tracking of his age largely academic. None can say how long Mordiggian has existed, for as far as one can look back into the past or forward into the future, the presence of his cult can be found if one searches hard enough.

Mordiggian has no body. He appears as a cloud of mobile, malevolent darkness and shadow that can change its outline and shape at will. He is fond of appearing as an immense graveworm or limbless giant made of darkness, and when he desires a meal, he can form tentacles of solid darkness to pluck up his feast.

Ghouls, particularly those that dwell in Leng, often venerate Mordiggian with a ferocious zeal. They consider ghoulish worshipers of other deities, particularly of the demon lord Kabriri, to be heretics and work to eradicate such blasphemers whenever they are found. Although worship of Mordiggian has become quite rare on Golarion as other death gods have gained more prominence, his cult is patient and willing to simply wait for the Charnel God’s inevitable return to power.

Mordiggian’s Cult

Mordiggian’s worshipers venerate him as a death god, and his worship is openly allowed in some cities. In these cases, his temple also serves to dispose of all of the city’s dead, yet the faithful’s exact method for dealing with corpses is subject to fearful whispers among the nonbelievers. His temples consist of either underground vaults hidden below graveyards or towering cathedrallike structures containing mazes of rooms. Mordiggian grants access to the domains of Chaos, Darkness, Death, and Evil, and to the subdomains of Entropy (Pathfinder Campaign Setting: Inner Sea Gods 224), Loss, Night, and Undead. His favored weapon is the scimitar.