Mortal minds are, by definition, limited. When exposed to that which lies beyond, they can be damaged. When filled with the unknown, they can overflow. In the face of the Elder Beings, they can break entirely.
The Mythos entities are a challenge not just because of their physical power and the danger they present, but because the mere presence of these soul-shattering beings can fracture a mortal psyche. One cannot even learn of the terrors of the Cthulhu Mythos without suffering a profound effect, much less face them in person, and some of the best-known effects are madness, unreasoning terror, and ongoing neuroses.
These rules will teach you how to implement madness and insanity rules in your game. This also leads to the fun roleplaying challenges in portraying mental quirks and unique psychoses that add depth to your characters.
Thereafter, this section discusses the sanity straining depths of the Aklo language.
The final section provides basic rules for visiting the partly-mental, yet wholly physical plane of existence known as the Dreamlands—home to Dreamlands cats, the gnorri, and the zoog as well as all sleeping material minds.
Dread and Insanity
Heroic characters featured in the typical fantasy setting are exposed to danger, mayhem, and violence as a regular part of their lives. As such, the concept of a doughty fighter, faithful cleric, jaded rogue, or potent wizard going mad because of something as minor as being startled by a monster or stumbling upon a dead body is not thematically appropriate. The potent dread and insanity described herein are reserved for truly dire and horrific circumstances. Exposure to the presence of an Elder Being, enduring the grueling mental assault of an eldritch magical attack, or even observing a creature whose very presence can instill supernatural fear or unhinge the capacity for sane thought can wreak havoc on the most heroic of adventurers.
The core of these rules are the concepts of dread and insanity. Dread can have minor effects, such as causing a character to become momentarily shaken, skittish, or distracted, but it can also have long-lasting or even deadly effects such as panick or heart attacks. Sufficient dread (amongst other equally dark circumstances) can cause a character to suffer insanity, which has more devastating effects in the long term.
Note that the rules presented here are not intended to be a realistic representation of mental illness, but merely a method to track the effects that exposure to supernatural awfulness can inflict upon heroes and villains alike. (For more on this point, see “Types of Insanity”.) In addition, the rules presented here are self-contained and should be relatively simple and straightforward.
Expand them in your game as you see fit.
Dread Threshold: Each character has a dread threshold equal to 3 + her Wisdom modifier. Dread gained beyond this number can drive the character insane as described below in addition to its usual effects.
Exposure to Dread
There are three typical catalysts that can cause dread: disturbing discovery (learning dire secret truths of the universe); supernatural influence (being affected by magical fear or insanity effects); and unnameable doom (being exposed to the true awfulness and mindblasting presence of a Great Old One or Outer God).
Disturbing Discovery: When a character makes a shocking discovery about the world, realizes that their actions have had horrific results, or is otherwise mentally stressed or traumatized by some terrible revelation, there is a chance that the character experiences dread.
Note that extraordinary effects that cause fear do not necessarily cause dread, including Intimidate checks and the frightful presence universal monster rule. The GM has final say on which disturbing discoveries have the potential to trigger insanity or dread, but it’s best to save these incidents for key plot points during a campaign rather than to use them frequently.
A character can attempt a Will save to avoid the dread effect of a disturbing discovery. The save DC and the duration of the dread depend upon how disturbing the discovery or trauma is. Success negates any dread.
A minor disturbing discovery (such as learning that the citizens of the strange town you’re visiting are in fact cannibals, or that the lonely traveler you invited into your home is in fact a vampire) has a DC of 10 and duration of 1d12 rounds. A moderate disturbing discovery (such as learning that the meat pie you ate at the local tavern was made of previous customers, or reading a particularly blasphemous and disturbing spellbook) has a DC of 15 and a duration of 1d12 x 10 minutes. A major disturbing discovery (such as realizing that your father was a deep one or that by activating the strange magical artifact in a dungeon you have transformed the entire populace of the city above into zombies) has a DC of 20 and a duration of 1d12 days.
As a rule, disturbing discoveries shouldn’t require a save DC higher than 20. If a discovery reveals a clear and present danger to the character or challenges her understanding of herself, she takes a –5 penalty on her saving throw, or –10 in extreme cases.
Supernatural Influence: When using the insanity and dread system presented in this book, magical fear and confusion effects cause dread, and the confused condition and insanity effects cause dread in addition to their usual effects. Insanity does not cause dread while it is not affecting the character (such as a phobia when the source of anxiety is not present). Dread instead replaces the typical effects of magical fear: this includes effects such as a fear spell, the despair aura of an undead mummy, and the bay of a yeth hound.
|Dread Stage||Dread Effect||Description|
|0||Unafraid||You are not suffering a dread effect.|
|1||Disturbed||You feel nervous and unsettled, but suffer no additional game effect.|
|2||Spooked||You take a –1 penalty on Will saves.|
|3||Unnerved||You take a –1 penalty on attack rolls, saving throws, skill checks, and ability checks.|
|4||Shaken||You are shaken.|
|5||Staggered||You are shaken and staggered.|
|6||Nauseated||You are shaken and nauseated.|
|7||Frightened||You are frightened.|
|8||Panicked||You are panicked.|
|9||Cowering||You become cowed with fear.|
|10||Faint/Heart Attack||You fall unconscious from horrific shock and must attempt a Fortitude save with the same DC as the effect that caused your dread; if you fail this Fortitude save, you also suffer a heart attack and take 2d6 points of Constitution damage.|
If you succeed at the Fortitude save or survive the effect of failure, you reduce your dread stage to 6 and awaken after 2d6 rounds. Another creature can attempt a DC 15 Heal check as a full-round action to awaken you early.
A character targeted by such an ability can attempt a saving throw against the ability as normal (using the source’s listed save DC), but on a failed save, the victim instead suffers the effect of dread (see below). If the effect would cause the frightened condition, the save is at a –5 penalty. If the effect would cause the panicked, terrified, horrified, paralyzed in fear, or cowering conditions, the save is at a –10 penalty. A dread effect caused by supernatural influence lasts as long as the associated fear effect would normally last.
Unnameable Doom: When a character first enters the area of influence of a Great Old One or Outer God, he must attempt a Will save against the entity’s influence DC to resist suffering the effects of dread.
The creature must attempt a new Will save whenever the influence increases in stage, but not each round spent in the area of influence, nor each time a creature exits and reenters the area of influence. A dread effect caused by an unnameable doom lasts as long as the creature remains within the area of influence, plus a number of hours thereafter equal to the influence’s CR.
Effects of Dread
There are ten stages of dread, each more traumatic than the last. A creature not affected by dread is at stage 0. (It cannot have a dread stage of less than 0 unless it is using the optional Dread Resistance rules in the sidebar or is a delirium warrior.) When a character fails a Will save to resist dread, her dread progresses 1 stage from her current dread stage, plus 1 additional stage for every 5 by which she failed the Will save.
When a dread effect reaches the end of its duration, it doesn’t always vanish completely. Instead, the victim’s dread decreases by a number of stages equal to her Wisdom modifier (minimum 1 stage). She suffers this reduced level of dread for the same duration before it decreases again until she reaches stage 0 (or until her dread increases again). At the start of a round in which a victim is suffering an ongoing dread effect of stage 5 or higher, the victim can attempt a Will save (at the same DC as the initial effect). Success decreases the dread’s stage immediately. This save can’t reduce the dread below stage 4. A character at dread stage 10 that fails this save can’t attempt it again for 1 day. The DC is the same as when the character gained the dread.
If the effect did not allow a save, use the appropriate DC it would have had if it allowed a save (such as 10 + 1/2 HD + Charisma modifier for a monster’s ability) or DC 15 if there is no obvious counterpart.
Dread is a mind-affecting fear effect. Unlike other supernatural fear effects, dread does not itself cause a character to suffer additional dread. An effect that removes a fear effect reduces the character’s dread by 3 stages if it could remove panicked, 2 stages if it could remove frightened, or 1 stage if it could remove shaken. Creatures immune to mind-affecting effects are immune to dread and insanity.
Combining Dread Effects: When a character gains a new dread effect in addition to an existing one, add their stages together to determine the character’s current dread. This summed dread has the longer of the two durations and the higher of the two DCs to remove. Any secondary effects follow their normal rules. A character’s dread stage can never be higher than 10.
Optional Rule: Dread Resistance
If you use dread and insanity in your game, you should strongly consider also using this optional rule. Under this rule, class features and creature abilities that grant immunity to fear instead grant dread resistance. Dread resistance grants the creature a +5 bonus on saving throws against dread. In addition, when unaffected by dread, dread resistant creatures treat their starting dread stage as –2 rather than 0.
Dread and Mundane Fear: If a character experiences both mundane fear and dread, both apply normally and their effects do not stack.
Insanity is a long-term affliction that has specific effects on a character and his abilities. Insanity does not in and of itself cause or worsen dread. Rather, insanity functions similar to a disease: it afflicts a character with a specific disadvantage that remains until the insanity is cured or the character recovers from it. Insanity is less common and immediate compared to dread, and it is potentially devastating over the long term. There are numerous forms of insanity detailed on the following pages. When a character gains an insanity, the GM selects an appropriate insanity (or rolls one randomly) from the list. It’s possible to suffer from multiple forms of insanity.
There are four ways in which a character can be driven insane by events that occur during a game: overwhelming dread (being exposed to several dread effects within a 24-hour period), cataclysmic mental trauma, confusion effects, or effects that directly afflict the character with insanity. All insanities are mind-affecting effects and creatures immune to mind-affecting effects cannot gain an insanity under these rules.
Overwhelming Dread: Whenever a character rolls a natural 1 on a saving throw against a dread effect, she must succeed at a Will save against the same DC to avoid contracting an insanity. In addition, if a character’s dread increases to a stage higher than her dread threshold, she must succeed at an immediate Will save against the dread effect DC or contract an insanity.
Confusion Effects: When a character suffers from a confusion effect caused by a magical source, there is a percentage chance equal to the save DC of the confusion effect that she develops an insanity that persists after the confusion effect ends.
Insanity Effects: Rather than gaining a permanent state of confusion, a character who is affected by an insanity spell or a symbol of insanity immediately gains a specific form of insanity chosen by the caster.
All insanities have a DC that represents the insanity’s strength, depending on what caused the insanity.
Overwhelming Dread: Insanity caused as a result of overwhelming dread has a DC equal to 10 + the stage of dread the victim was suffering when he became overwhelmed with dread.
Cataclysmic Mental Trauma: Insanity caused by cataclysmic mental trauma has a DC of 15.
Confusion and Insanity Effects: Insanity caused by a magical confusion or insanity effect has a DC equal to the original effect’s save DC.
Multiple Insanities: Whenever a character gains a new form of insanity, the DCs of his existing insanities each increase by 2. If the new insanity gained is one the victim is already suffering from, that current insanity (and that insanity only) instead has its DC increased by 5.
Recovering from Insanity
Once per week, a character suffering an insanity can attempt a Will save against the insanity’s DC. On a success, the insanity’s DC is reduced by 1d4, but note that some forms of insanity have effects that trigger if the character fails this save. As long as the insanity has a DC of at least 1, the character continues to suffer the full effects of the insanity, although it becomes easier to resist its effects and recover as the DC goes down. Once the insanity reaches a DC of 0, the character is cured and that particular insanity no longer affects him.
Insanity can be treated with the Heal skill. First, the insanity must be identified. A character can identify an insanity with a successful Heal check against 5 + the insanity’s DC. Then, with 1 hour of effort per day in a week, the healer can treat it with a Heal check against the same DC at the end of the week. If the check succeeds, the patient receives a +2 bonus on the saving throw to reduce the sanity’s DC for that week.
- Greater restoration cures one insanity suffered by a creature (caster’s choice) and reduces the DC of all other insanities suffered by that creature by 2d6.
- Restoration reduces the DC of one insanity suffered by a creature by 2d6. If a target creature suffers from multiple insanities, the spell only affects the insanity with the lowest DC (chosen randomly in the event of a tie).
- Lesser restoration has no effect on insanity.
Types of Insanity
The following table summarizes the most common forms of insanity that plague adventurers who face the horrors of the Mythos. When a character gains an insanity, roll on the table to determine the nature of the affliction or choose one appropriate to your character.
Alternatively, the GM can assign an insanity to match the cause or craft a new one altogether.
Phobia: A phobia is an irrational fear of some (usually commonplace) object or situation. A character suffering from a phobia takes a –2 morale penalty on attack rolls, skill checks, and Will saving throws when the source of his phobia is present. Additionally, if a phobic character is directly confronted by his fear, he must succeed at a Will save against the DC of his phobia or suffer dread.
Obsession: Sometimes referred to as a fixation or (archaically) as a mania, the character develops an irrational obsession with a (usually inappropriate) particular object or situation. A character suffering from obsession takes a –2 morale penalty on attack rolls, skill checks, and Will saving throws when the source of his obsession is present but not in his immediate possession. Additionally, if a character is directly confronted by his obsession or possesses it in some way, he must succeed at a Will save against the DC of his obsession or become completely enthralled by the object. (For instance, a bibliomaniacal character might suffer the noted penalty while in a library but only become enthralled when actually reading a book, whereas an egomaniacal character might suffer the penalty in a room full of mirrors but become enthralled when actually holding a mirror or grappling with a doppelganger.) While enthralled, the character can do nothing but attempt to interact with this object in a manner appropriate to his insanity. He still tries to avoid danger and protects himself from harm, but otherwise remains fixated. He can attempt a new Will save once per round to overcome this obsession.
If you wish to use these rules for enemies and effects designed for sanity point rules, such as those described in Pathfinder RPG Horror Adventures, make the following adjustments.
Any effect that would deal sanity damage instead inflicts dread for a number of rounds equal to the number of points of sanity damage.
The character’s dread increases by 1 stage + 1 additional stage per 3 points of sanity damage.
Any effect that would remove sanity damage instead lowers the character’s dread by 1 stage +1 additional stage per 3 points of sanity damage removed.
Erratic Behavior: A character suffering from erratic behavior seems strange and unreliable. Her friends can never predict exactly what she will do next, and sometimes even she can’t say for certain. She doesn’t always control her own body. Such an insanity might manifest as strange facial tics or violent spasms.
A character suffering from erratic behavior suffers a –6 penalty on Charisma-based skills with strangers unfamiliar with her behavior and can never take 10 or 20 on a skill check based on a physical ability score (Strength, Dexterity, or Constitution) because there is always a chance her body will betray her if she lets her focus waver.
Additionally, a character suffering from erratic behavior who enters into a stressful situation (such as combat) must attempt a Will save against her insanity’s DC on her turn each round. If she fails, her body acts independently of her will, with the GM determining her action randomly (per the confusion spell). This confusion effect cannot itself cause dread or insanity.
Hallucinations: A hallucinating character perceives things that aren’t there. These perceptions may be visual or auditory or might affect the other senses. It is difficult to tell the false perceptions from the real.
When a hallucinating character enters a stressful situation (such as combat) he must attempt a Will save against his insanity’s DC. If he fails, the character is overwhelmed by a barrage of sensory input and becomes confused, and his actions are determined randomly on a round-by-round basis (this confusion effect cannot itself cause dread or insanity). A confused hallucinating character can attempt a new Will save once per round to recover his senses; otherwise he remains confused until he is rendered unconscious, slain, or subjected to an effect that removes confusion (such as calm emotions), or another character successfully counsels the confused character with a Diplomacy check (DC = the hallucination insanity’s save DC) as a full-round action.
Paranoia: A paranoid character is convinced that the world and all that dwells within it are out to get him. Paranoid characters constantly suffer from the following conditions.
A paranoid character takes a –6 circumstance penalty on Charisma-based skill checks.
A paranoid character takes a –2 circumstance penalty on Will saving throws.
A paranoid character never willingly accepts aid (such as healing or a beneficial spell) from another creature, unless he manages to suppress his paranoia with a successful Will save against the paranoia’s DC.
These rules alter the way spells that cause permanent insanity effects (such as insanity or symbol of insanity) function. Rather than causing a permanent state of confusion, a character who is affected by an insanity spell or a symbol of insanity immediately becomes afflicted by a specific form of insanity, as detailed on the following pages.
These effects completely bypass causing dread.
Delusion: A character suffering from delusion may believe any number of odd things about herself. For instance, she may believe she is suffering from a specific physical condition (such as blindness, deafness, nausea, paralysis, etc.) when in fact she is perfectly healthy.
It’s also possible the character believes something unrealistically positive about herself, such as that she is divine, cannot be injured by mundane weapons, or is immune to fire. Nonetheless, upon awakening from a period of 8 hours of rest, the afflicted character must succeed at a Will saving throw against the insanity DC or she experiences the full effects of the imagined physical condition, suffering any detrimental physical condition or a circumstance penalty of -4 AC and saving throws against a particular sort of attack (GM’s discretion). On a success, the victim avoids the condition until she fails her next Will save to suppress her delusion. Failure indicates that the victim suffers from her imagined physical condition until the next time she succeeds at a Will save (after 8 hours of rest) to suppress the delusion.
Dissociation: These insanities are complex and fairly rare. A character suffering from dissociation finds himself a stranger in his own mind. Most cases of dissociation (80%) are forms of amnesia, while the remainder are cases of mental fragmentation that can manifest as multiple personalities.
Amnesia: A character suffering from amnesia cannot remember things; his name, his skills, and his past are all equal mysteries. He can build new memories, but any memories that existed before he became an amnesiac are suppressed. This terrible condition causes intense feelings of self-doubt and depression, and imposes a –6 morale penalty on Will saving throws and skill checks.
Worse, the amnesiac loses much of his ability for as long as his amnesia lasts. His physical memory remains, so he retains his base attack bonus, base saving throw bonuses, defense and reputation bonuses, Strength-, Dexterity-, and Constitution-based skills, and his Hit Dice (and hit points), but his class abilities, feats, and Intelligence-, Wisdom-, and Charisma-based skill ranks are lost until the amnesia is cured. If a character gains class levels while suffering from amnesia, he gains levels starting at 1st-level, as if he had no prior levels of any class (even if the class he takes a level in is a class he had prior to becoming amnesiac). If his amnesia is later cured, he regains all class abilities, feats, and skill ranks, and levels taken while he was suffering from amnesia increase his overall class level.
Multiple Personality Fragmentation: This is a complicated dissociation that manifests as two or more distinct and different personalities within the same body and mind. The number of additional personalities the victim manifests equals the DC of the insanity divided by 5 (rounded up to the nearest whole number). The GM should develop these additional personalities in consultation with the player.
Each morning, and each time the character suffers a dread effect, a character with personality fragmentation must succeed at a Will save against his insanity’s DC.
Failure indicates that a different personality takes over.
A character’s memories and skills remain unchanged, but the various personalities have no knowledge of each other and deny that these other personalities exist, sometimes violently. Characters with multiple personality fragmentation take a –6 circumstance penalty on Will saving throws and Wisdom-based skill checks. If a character fails a Will save against his insanity by 5 or more, he develops a new personality, in addition to his existing personas.
Psychosis: This complex insanity fills the victim with hatred for the world. His alignment becomes chaotic evil. He can suppress his psychosis for a period of 1 day by succeeding at a Will save against the DC of his insanity, allowing him to retain his previous alignment for that 1 day. If he fails, he cannot help but plot and plan the death and destruction of his friends and enemies alike. A psychotic character is quite adept at hiding his psychosis, and gains a +10 competence bonus on Bluff checks when attempting to act like his former self, feign sanity, or resist attempts to reveal his psychosis. A psychotic character always attempts Bluff checks when someone tries to diagnose him.
For the most part, the impact of psychosis must be roleplayed, although not all players find entertainment in roleplaying someone who’s trying to do in his friends.
In such cases, the GM should assume control of the character for as long as his psychosis lasts and give the player control once more upon a successful Will save to suppress the psychosis.
Playing Characters with Insanity
In the course of interacting with horrors from beyond space and time, it is not just possible but very probable that a character may go mad from unwanted revelations, terror, or incomprehensible new realities.
But this doesn’t mean the character ceases to be playable; now the player gets to play a character with interesting new quirks and behaviors and really stretch their roleplaying legs.
|1–5||Phobia (roll on Table: Random Phobias)|
|6–8||Obsession (roll on Table: Random Obsessions)|
|13||Demons or devils||Demonophobia|
|7–8||Dead things||Thanatomania or Necrophilia|
Degrees of Madness
The first thing you need to determine is just how insane a character is. For ease, madness can typically be subdivided into three categories.
First Degree: Neurotic Aftereffects After a brush with dread, or after recovering from a psychotic episode, it is unlikely that a person will completely return to normal. Instead, he will have quirks, nervous tics, and a somewhat shaky grasp of the world. If his insanity was instigated by reading terrible tomes, for instance, then other books may make him nervous or even give him a panic attack.
He may hoard objects or avoid keeping anything. He may be constantly concerned about the possibility of insects crawling under his skin. He might hear voices but (usually) know that they are not real.
Look for quirks to make your character fun, but not unplayable.
Second Degree: Psychotic but Aware At this stage, the character, while clearly insane, is aware of their surroundings and capable of interacting with other characters, and can take normal actions, such as walking, eating, and possibly fighting. Picture a character in a film or book who has gone beyond being simply “odd” to the point of demonstrating unusual behaviors and attitudes at all times, which flavor their methods and interactions with others but still allow them to function.
Remember that playing an insane character is not the same as playing an annoying character. Instead, strive to play your insane character with humor and intelligence. One critical aspect to madness is to never confuse it with stupidity: an insane character may interpret her surroundings or events incorrectly, but within her (skewed) worldview, her actions are often logical. Neither should you confuse insanity with comic relief: an insane character can be entertaining but not a constant subject of ridicule or the butt of every joke.
Your character should enrich the game rather than detract from it—the way any character does.
Also be aware that while your character’s view of reality may be distorted, it is also possible (even likely) that due to her contact with the Mythos, her view may be closer to the actual truth. For example, a person who sees things or hears voices that no one else can see or hear may seem insane, but the person’s condition could be caused by a permanent alteration to her brain that allows her to see or hear real entities in a parallel dimension to our own! Most importantly, there is no way for anyone to confirm whether the voices and hallucinations are real, short of acquiring the insanity themselves.
Consider David Cronenberg’s The Fly (spoiler alert). The main character, who is genetically half-fly, wants to return to his human condition, and comes up with a plan: he’ll place his girlfriend, pregnant with his child, into the teleporter and merge with her. The resulting monstrosity will have three times as many human genes as a fly, and thus make him far more human. This is perfectly logical, yet horrifying and certainly not something a sane person would do.
Second Degree characters often behave as villains, though this is not necessarily intentional. They can be tricked into doing the right thing by other players who pander to their madness or try to get them to rise above it.
Third Degree: Stark Raving Sometimes a character has been driven so insane that the player is forced to relinquish control to the GM.
The sorceress is cowering in a corner, clawing at the air and babbling in an unknown language, or the paladin throws away his weapons and runs blindly through the forest shrieking. Typically, this extreme madness is only a temporary condition, and eventually the player can regain some control. of course, in some cases, this can indeed be permanent, in which case the character becomes a GM tool, and is retired from active play.
The player should create a new character to continue the adventure.
As noted earlier in this chapter, the insanities listed above are not intended to reflect real-world mental illnesses, but are instead supernaturally induced conditions that afflict imaginary heroes in play. They are included strictly for thematic purposes, as the descent into madness is an inescapable part of a Mythos game.
Considering that mental illness is a real world affliction that many suffer from and does not necessarily present in an obvious way, it is extremely important that GMs be aware of and considerate of players when it comes to this topic. If a player is uncomfortable with one of the insanities discussed, do not use it in your game. It is always incumbent upon the GM to be cognizant of player needs and tailor their games appropriately.
Ia! Ia! Cthulhu fhtagn: An Aklo Primer
Aklo is a pre-human occult language, common to many primeval and unearthly species. Fey, ancient races, and entities from the Void are the most common speakers of Aklo. It is no one’s native tongue but rather a sort of lingua franca, spoken by many beings as a way to communicate across cultures. A member of an ancient race might wish to speak only with a fellow Aklo speaker so that important arcane concepts are correctly communicated, for example.
Aklo is not fully usable by or comprehensible by mortals, as its concepts and grammar are not compatible with a sane mind. Also, many parts of the Aklo language function on a different level than mere vocal communication. Spoken Aklo contains an empathic component best conveyed through telepathy, which resonates within the written form as well.
The tenses of Aklo are not simply past, present, and future, but rather alter like the fluid shifting of other realities and dimensions unreachable by mortals. Aklo is the language best suited to entities that perceive the passage of time differently from mortals: as a collection of events rather than as a stream. Creatures that have undergone profound changes in their forms (such as liches) can also make good use of Aklo.
Not all speakers comprehend Aklo at the same level.
Some have access only to the fundamental principles of the tongue—those parts most similar to mortal speech.
Others plunge so deep into the ideas of Aklo that they find it almost impossible to impart information to mortals.
Beings incapable of verbal speech (such as Gugs) may still be able to understand Aklo but cannot speak or otherwise transmit it. They may, however, be able to write its glyphs.
Knowledge and wisdom are difficult to transmit fully by translating them from Aklo to a mortal language, and sometimes outright impossible. Thus, some information is always lost or warped.
Prolonged exposure to Aklo can permanently change a mortal’s understanding of time or reality— typically to his detriment in functioning in the mortal realm. Attempts to understand more than a primitive smattering (a sort of pidgin Aklo) can result in madness, mania, or even death. Generally, this is represented in the dread and insanity rules as a moderate or major disturbing discovery (previously described in this Chapter).
The effects of Aklo echo through its written form as well, so mortals must beware even tomes written in this tongue. While a few Aklo concepts can be delivered through other alphabets, typically the unique Aklo glyph system is necessary for full communication.
Aklo Speakers: The following creatures normally know at least some Aklo and may be fluent in it: abyssal custodian, byakhee, dark young, denizen of Leng, elder thing, eremite, fire vampire, flying polyp, formless spawn, ghoul (Mythos), gnoph-keh, gug (understand and write only), Great Old One (all), Outer God, hunting horror, migo, moonbeast, nightgaunt (understand only), satyr (Mythos), serpentfolk, servitor of the Outer Gods, daughter of Shug-Niggurath, star vampire, starspawn, Mythos undead, yithian.
Additionally, here is a reference of creatures that speak Aklo, organized by monster type:
Aberration: aatheriexa, aboleth, argus, azruverda, blightspawn, conqueror worm, cuero, decapus, dossenus, drakainia, dream naga, fleshdreg flumph, flying polyp, ghorazagh, gibbering mouther, grick, horla, hundun, ike-turso, incutilis, leng hound, moonbeast, lunar naga, slime naga, neh-thalggu, neothelid, omnipath, rhu-chalik, roper, sagari, seugathi, shriezyx, sinspawn (all), snallygaster, somalcygot, syricta, thought eater, urhag, vampiric mist, veiled master, vemerak, willow-o-wisp, wizard’s shackle (can’t speak), yaddithian, yangethe, yithian.
Fey: alp, alpluachra, banelight, bogeyman, gremlin (hobkins, nuno), lampad, lurker in light, muhuru, nuckelavee, quikling, red cap, sangoi, shadow collector, svartalfar, tunche, vilderavn, whisperer, wild hunt (archer, monarch, scout).
Magical Beast: baku, behemoth (all) (cannot speak), bhole (rarely speaks), catoblepas, chupacabra, goezspall, hivemind swarm, kamadan, leng spider, mngwa (can’t speak), ouroboros, phase spider, ratling, seaweed siren, spider eater (can’t speak), su (can’t speak), tarrasque (can’t speak), thrasfyr, voonith, witchcrow, xanthos.
Outsider: archdevils (all), archon (exscinder), caulborn, daemon (venedaemon), Empyreal Lord (Black Butterfly), hound of tindalos, hypnalis, manasaputra (solar pitri, twilight pitri), sceaduinar, shadow creature, shae, soulsilver, undefhan.
Sandy Petersen’s Cthulhu Mythos, © 2017, Petersen Games; Authors: Sandy Petersen, Arthur Petersen, Ian Starcher.