Call of Cthulhu 7e Magic Guide: How Spells Work, What They Cost, Contact Spells, and Mythos Tomes

Introduction

Magic in Call of Cthulhu 7e is forbidden procedure, a long way from a way to level up your character. An investigator learns something that should not fit in a human mind, pays for the attempt, and finds out whether the universe notices in the worst possible way. A spell can solve a narrow problem while costing Sanity, time, safety, and sometimes a piece of the caster that never comes back. A Mythos tome can hand the group exactly the clue it needs and leave the reader less able to face what comes next.

This guide covers the whole system in one place: how spells are learned and cast, what the first casting roll and a pushed casting really mean, the full bill a ritual can run up, how Contact spells differ from Call and Summon magic, and how tomes are read and studied. It gives players a way to decide when magic is worth it, and Keepers a way to make supernatural knowledge useful, dangerous, and a source of new scenes. Each individual spell entry in the Keeper Rulebook's Grimoire still controls its own requirements, targets, timing, and costs.

Hot Take

The best Call of Cthulhu spell is usually the one the investigators refuse to cast until every alternative is worse. A tome earns its place the same way: the valuable one tells the group what not to do, points at the real threat, and makes opening it feel like a choice they may regret. If spells and books arrive as rewards, magic turns the game into a different genre. If every ritual makes the table ask "what will this cost us, and can we survive being seen doing it?", magic is one more terrible lead in the investigation.

Forbidden Knowledge Is Evidence, Not Loot

An investigator does not normally set out to become a sorcerer. They set out to explain a disappearance, stop a murder, identify a cult, protect a friend, or survive one more night. Magic and tomes enter that work as dangerous evidence. They can reveal a pattern, name an enemy, show a weakness, or explain what a ritual is trying to accomplish. They also bring risks that ordinary research cannot contain.

Treat the discovery of a spell or a book as a change in the investigation. The group has learned that a thing exists, that someone believed it could be used, and that the author or previous owner paid a price to know it. The first question is not "What do we get?" It is "What problem does this create, and what does it let us understand?"

That framing keeps supernatural knowledge inside the horror genre. A locked tome in a university collection can be a clue, a liability, a bargaining chip, an invitation to a cult, or the reason an enemy finds the investigators. It does not need to be a permanent upgrade to matter.

The Keeper Rulebook says as much. Investigators mostly experience magic from the outside, as targets or witnesses, and rarely become mages because the knowledge required usually drives them mad first. Spells learned in a published scenario may only be useful for that one adventure. Common ways magic reaches the table:

• A cult ritual that has to be interrupted before it completes.
• A victim altered by an unknown ceremony or object.
• A hidden notation in a diary that explains a symbol found at several crime scenes.
• A spell the group learns only to recognize its effects or undo one part of its work.
• A book that a missing scholar protected, feared, or tried to destroy.
• A contact who knows the procedure but expects an ugly favor in exchange.

In each case, start with the fictional question. What did the magic do? What conditions made it possible? Who benefits if it continues? What would stop it? Those questions lead to investigation and a plan. Asking which spell has the most raw power leads nowhere useful.

The Occult Is Not Automatically the Mythos

Investigators will meet rituals, folklore, spiritualism, frauds, and occult beliefs that are not real Mythos magic. A fake seance can still conceal a murder. An old charm may be cultural history rather than a spell. A cultist may sincerely misunderstand the forces they claim to serve. The rules leave earthly "magick" to the Keeper: it may be real or fraudulent, and if it is real, the suggestion is to run it with the same procedures as Mythos magic and tie it to the Occult skill.

Do not assume every strange symbol needs a casting cost or every occultist is a competent sorcerer. Investigate first. The group may need Anthropology, History, Occult, Library Use, a language skill, or an expert contact before it knows whether a supernatural claim is real. That uncertainty keeps mundane inquiry useful even in a campaign where magic exists.

How Magic Works

Most fantasy games teach players to ask what their characters can do. Call of Cthulhu asks what they are prepared to do. The rulebook describes Mythos spells as formally constructed: one wrong word or gesture can disrupt the spell at best or make it go horribly wrong at worst. Few can be performed quickly, and many need exacting conditions and lengthy rites. Costs and effects are often unknown to the caster at first.

Spells Are Procedures, Not Buttons

A spell generally has several moving parts:

• Knowledge of the spell itself.
• The time, words, gestures, and materials it requires.
• A place where the investigators can perform it without immediate interference.
• The listed personal cost, often paid before anyone knows whether the attempt helps.
• A result that may create new evidence, attention, or danger even when it succeeds.

The individual spell entry is the authority. Some rituals are quick enough to attempt under pressure. Many are not. Some demand a particular target, object, or astronomical condition. Some make the caster visibly strange; others leave only a circle on the floor, burnt incense, or an investigator who cannot explain where the missing hours went.

That makes magic an investigative tool before it is a tactical one. A spell might identify a threat, protect a location, open communication with something no one should contact, or reveal a fact the mundane investigation cannot reach. Each use matters because it changes the group's choices, not because it removes their problems.

Before an investigator casts, establish five facts:

1. What exact result does the investigator want?
2. What does the spell require in time, place, people, objects, or conditions?
3. What is known about its Magic Point, Sanity, and other costs?
4. What will failure, interruption, or success make worse?
5. What nonmagical plan remains if the group refuses or cannot cast it?

If the group can answer all five and the outcome directly solves the immediate problem, casting may be the right call. If all anyone knows is that the spell "might help," it is usually time to research, observe, or find a safer route.

What an Investigator Must Know Before Casting

The caster must know the spell. Having a book in a satchel, seeing a ritual once, or owning an artifact that looks related is not the same as understanding the procedure. Make this clear early, especially when a group finds a tempting grimoire in the middle of a crisis.

Knowing a spell means being able to recite its chant or rite, sometimes long and complex, in authoritative tones. The caster usually needs complete freedom of movement, because gesture can matter as much as chant. An investigator tied to a chair, gagged, wrestling a cultist, or whispering through a broken jaw is in no position to finish a demanding ritual.

Before a player commits, ask practical questions:

• What does the investigator think this spell will do?
• Which parts of the spell description can they satisfy right now?
• How long do they have before the threat changes the situation?
• Who keeps watch, handles the materials, or gets everyone out afterward?
• What will the room look and sound like to an outsider?

These questions turn a line on the character sheet into a scene, and none of them is a trivia trap. A group that chooses the locked archive over the alley, sends the professor for a needed item, and posts someone on the stairs has made magic part of the investigation.

Learning a Spell

Spells come from a Mythos tome, a human teacher, or the Mythos itself. Learning from a book is by far the most common route. None of these sources is safe, and they should not feel interchangeable. Learning a spell does not cost Sanity by itself; casting it does.

From a Mythos Tome

The investigator must have completed at least an initial reading of the book. The Keeper then summarizes each spell it contains in a sentence or two, and the rulebook advises against using the rulebook name. A line about a great winged beast brought forth from the void is more credible than "Summon Byakhee." The investigator chooses which spell to pursue.

Learning takes hours, days, weeks, or months, typically 2D6 weeks at the Keeper's discretion, and can be picked up and set aside as convenient. That benchmark is a reminder that occult study is usually a downtime decision, not an emergency button.

The normal test is a Hard INT roll, though the Keeper may grant automatic success when the scenario supports it. A researcher with months, a careful translation, a patient teacher, and a safe study room does not need the same friction as someone decoding water-damaged pages between clues. A failure means the spell is not learned: the knowledge stays fragmented, contradictory, or just beyond a human pattern of thought.

A player can push a failed learning roll with a real fictional method, such as locking the investigator away in isolation until the spell is mastered. If the push fails, the rulebook tells the Keeper to be creative and include Sanity loss and strange magical effects on the investigator and their surroundings. Let the consequence come from the book and the scene. A marine biologist dreams of a drowned library and wakes with salt under every fingernail. A historian recognizes the handwriting in the margins as their own.

An investigator in no hurry can keep working without pushing. The Keeper decides when the next INT roll comes, perhaps once every two weeks, though scenario pacing matters more than the calendar. Some failed approaches should need a new lead, a better translation, or a change in circumstances first.

From a Teacher or Entity

Someone who knows a spell can teach it, and one-on-one teaching is faster than a book, typically 1D8 days, using the same rules. That makes a useful relationship hook, never a consequence-free tutoring service. What does the teacher want? Why do they trust the investigator? What happens if the student becomes a rival, a witness, or a liability?

A Mythos entity may hand over a written copy, but more often it teaches through dreams or visions, each episode disturbing and alienating. It might even implant a complete spell by telepathy, an experience that could send the character straight to the asylum. The rulebook suggests a Sanity loss of at least 1D6. The investigator gets knowledge and also a connection: a recurring dream, a phrase heard in the wrong voices, an expectation from the thing that taught them. Investigators rarely learn this way; cultists often do.

After the process, the Keeper may require an INT roll to retain the spell. On a failure, the process starts again. The character has not forgotten ordinary facts; the human mind has rejected the shape of what it briefly understood.

The First Casting Is a Hard POW Roll

A casting roll is only required the first time a character casts a newly learned spell, and it is a Hard POW roll. Once the spell has been cast successfully, even through a pushed roll, later uses need no casting roll. Non-player characters and monsters never make casting rolls.

That makes the first casting a real scene. The investigator has studied the words, arranged the materials, and reached the moment where theory becomes contact. Their will has to hold the rite together long enough for something to answer.

Do not hide spells until a character has exceptional POW. The uncertainty is the point, and players improve their odds through actual preparation: a defensible location, knowledge of what the ritual needs, a caster who can move and speak, and a clear view of whether the payoff is worth the risk. After the first success, the spell is familiar in the most unsettling sense. It is no less dangerous and no less costly; the character simply no longer has to prove they can start it.

What a Failed Casting Means

On a failed first casting roll, nothing happens. The investigator has still attempted the procedure and paid its cost. The rules then give three choices: give up on the spell, push by making a second attempt (paying the costs again) either immediately or at any later time, or go back to the source and relearn the spell from scratch, usually another 2D6 weeks and a Hard INT roll, before making a fresh initial casting roll. Relearning is the cautious route. Pushing is not.

Make the failure readable in the fiction. The candle gutters, the voices do not align, the air turns painfully still, or the target's reflection looks back a moment too late. The players should understand that they reached toward the impossible and failed to make it hold, not that they missed a number.

Walking away is a valid decision. A failed first casting can push the group back toward mundane evidence, escape, negotiation, or another occult lead, with no obligation to try again. In a horror game, refusing to double down is often good judgment.

Pushing a Casting Roll

A pushed casting roll is a bargain. The investigator pays the spell's costs again and makes the attempt on much worse terms. If the pushed roll succeeds, the spell works normally with no further harm. If it fails, the spell still works. The rulebook puts it plainly: a spell can always be cast, and the casting roll measures the harm to the caster rather than whether the spell succeeds.

The price of a failed push is severe. The caster pays the spell's cost in Magic Points, Sanity, and POW again, multiplied by 1D6, and any Magic Point overspend comes from Hit Points. That can cause a major wound or death when pushing powerful spells. The Keeper also adds one or more side effects, which can hit the caster and anyone nearby. The rulebook's menu for lesser spells runs from blurred vision, disembodied voices, sudden winds, bleeding, and hallucinations to the smell of brimstone or an accidentally summoned monster. For powerful spells, such as those that call gods or cost POW, the options escalate to shaking earth, blood falling from the sky, a withered hand, unnatural aging, a swarm of attacking entities, being flung to a distant time or place, or a deity arriving by accident.

Pick or roll a side effect, then make it rhyme with the spell's purpose:

• A ward succeeds, but the caster cannot cross its boundary until dawn.
• A contact ritual reveals the answer, but something now knows the investigator's name and address.
• A spell that hides the group works, but every nearby witness loses the same hour of memory and starts asking why.
• A protective rite saves an ally but moves the ally's nightmare onto the caster for the rest of the scenario.

The consequence should create a playable problem without erasing the success. The spell has to matter, and so does the cost.

Example: The Cellar Door

Mara has learned a protective ritual from a dead antiquarian's notebook. The investigators need to keep an inhuman pursuer out of a boarding-house cellar long enough to burn evidence and escape through the coal chute. The spell needs a prepared boundary, an uninterrupted chant, and room to move through the final gestures.

The group does not cast in the first room it finds. They clear the cellar threshold, put one investigator on the door, and send another to prepare the escape route. Mara fails the Hard POW roll. The chalk line blackens, but the cold pressure on the other side remains.

The players now have real options: abandon the ritual and use the coal chute, or push. Mara pushes and fails again. The boundary seals, buying the time they need, but she pays the multiplied cost, and the Keeper decides she cannot leave the marked area until the rite ends. The others must wait for her, find a safe way to break the ritual, or leave her with the thing at the door. The group got a real benefit, and the scene got sharper instead of shorter.

Disruption, Evidence, and Preparation

A spell is disrupted if the caster is significantly distracted during casting, for example by being struck or shot. The caster still pays the Sanity and Magic Point costs, and the Keeper can borrow from the failed-push side effects for what goes wrong.

This is why the rest of the group matters. A caster needs cover, warning, and room to work. The strongest magical plan usually starts with mundane play: lock the door, post a lookout, remove the obvious interruption, collect the materials, and decide what the non-casters do if the ritual turns dangerous. Keep preparation specific rather than a shopping list:

• Find a location that supports the rite rather than one that merely hides it.
• Confirm the caster can speak and move through the required steps.
• Decide who handles interruptions and who watches for witnesses.
• Keep an exit open in case the effect draws attention.
• Tell the Keeper what the investigators are trying to accomplish, not only the spell name.

Evidence is another dial. The rulebook advises keeping visible signs of casting low-key, such as an odd gesture or an unusual ingredient, though effects can range up to roars from beyond, gouts of fire, auroras, the stench of sulfur, or howling animals. Pick what suits the campaign's tone and gives the investigators a new fact to manage.

Belief and the Price of Knowing

Call of Cthulhu separates knowing facts about the Mythos from accepting that they are real. A non-believer who reads a tome still gains its Cthulhu Mythos skill and the matching drop in maximum Sanity, but loses no current Sanity for the reading. A non-believer can read Mythos books and learn spells. They cannot cast them.

Belief eventually arrives. Meeting a clearly unearthly being or a manifestation of a Mythos god always breaks the facade, and a player can choose to have the investigator believe at any time. At that moment the investigator loses Sanity equal to their current Cthulhu Mythos skill. Some firsthand experiences can still be rationalized: an investigator who passes the Sanity roll for seeing a deep one loses nothing and might explain it away as a human mutation.

Do not treat disbelief as an immunity strategy. It is a roleplaying pressure point, and the Keeper should apply the line honestly. Belief also changes what a spell means emotionally. Before it, the investigator is studying a bizarre historical curiosity. After it, they are knowingly using a method that reaches beyond the world, and that realization is often more frightening than the ritual.

Mythos Magic Costs

A spell's cost is not flavor text after the interesting part. It is the interesting part. The Grimoire describes every spell as three parts: a cost, a description, and an effect. The effect tells the group what they might gain. The cost tells them what the investigator has agreed to lose, and the rules work best when that price is discussed before the dice come out.

A Spell Has More Than One Price

The listed cost is usually Magic Points and Sanity, with permanent POW added when an effect is long-lasting or highly significant. Around those numbers sit other prices:

• Magic Points, the default expendable fuel.
• Sanity loss for manipulating Mythos forces.
• Permanent POW, for lasting or far-reaching magic.
• Hit Point damage when Magic Point spending runs past zero.
• Physical components, some reusable and some consumed.
• Casting time, from instantaneous to a week or longer.
• A required location, target, or condition that creates risk without a number attached.

Not every spell uses every category, and the listed spell is always the authority. A ritual that costs only Magic Points can still be dangerous because it takes a week and needs a particular place. A spell with modest Sanity loss can be ruinous because it also takes POW. The cheapest spell on paper is not always the cheapest spell: a low-point ritual that eats your only safe night, exposes your identity, and needs an illegal component can cost more than a dramatic effect with a bigger number beside it. Count everything, including the part of the case that now has to happen without the caster.

Magic Points: The Immediate Resource

Magic Points must, in most cases, be spent to cast spells, energize artifacts, and power gates. An investigator starts with Magic Points equal to one-fifth of POW, and they regenerate at one point per hour. That makes them the most recoverable common cost, but not a trivial one. A drained caster is vulnerable in the same scene, cannot safely repeat a ritual, and may need hours before another occult option is realistic.

Nearly all spells need their Magic Points (or POW) spent or the spell does not activate at all; there is no partial effect. If a spell needs five points and the caster has fewer, the shortfall comes from Hit Points. A Keeper who lets an investigator cast repeatedly during one crisis without tracking the pool removes the main reason the spell has a price. For pool size, recovery, and temporary excess points, see the Magic Points guide.

Sanity: The Cost of Making It Real

Manipulating Mythos forces costs Sanity in amounts that vary by spell. That loss is separate from the Sanity cost of reading a tome and from the loss for encountering whatever answers the spell. One casting scene can carry several mental costs: the listed cost, then the shock of seeing what arrived, then whatever the aftermath brings.

Describe the loss as an experience, not a receipt. The caster might lose a comforting memory, hear a familiar voice inside the chant, or become certain the room is watching them.

A character at zero Sanity can still cast, which is what explains cultists and ruined sorcerers. It is not an invitation to treat Sanity as spare fuel; a character at zero is already in catastrophic territory, handled through the game's insanity rules. When planning a cast, look at current Sanity and the likely exposure afterward. A caster who can absorb a 1D6 loss may still land near the 5-point temporary-insanity threshold if the ritual also brings something visible into the room.

POW: The Cost That Does Not Come Back

Some magic takes POW instead of, or in addition to, Magic Points. This is a permanent sacrifice, not a temporary drain. POW sets the Magic Point maximum, so lowering it shrinks the pool for the rest of the campaign.

POW costs suit effects that last, reach far, or transform the caster. Elder Sign, Bless Blade, Contact Deity, and every Gate creation are examples. They should make the group ask whether an immediate result justifies changing the investigator's baseline for good. Record the change immediately and recalculate the Magic Point maximum. Do not let a POW sacrifice blur into ordinary Magic Point spending because both involve mystical energy. One returns naturally. The other does not.

Spending your own Magic Points or POW takes only your will. Magic that drains POW from an unwilling target is a different thing: the rulebook notes that losing 10 POW involuntarily is a stronger sensation than losing the same number of Magic Points. It should feel like an assault on the self, not exhaustion.

Hit Points: When the Pool Is Empty

Once an investigator reaches zero Magic Points, further Magic Point costs come from Hit Points, one for one, and the Keeper narrates the harm: sores and cuts opening, blistering skin, blood from the eyes or ears. This can cause a major wound or death.

Suppose a caster has two Magic Points and tries a spell costing six. The two points are spent and the other four come from Hit Points. If the caster is already hurt, those four points may cause a major wound, force a CON roll to stay conscious, or put escape out of reach. Magic Points and Hit Points can recover at the same time, but the lost Hit Points heal under the normal Wounds and Healing rules. A refilled pool does not close the wound.

Magical attacks can also drain Magic Points before the group chooses to cast. A character who starts a confrontation at zero is not out of options; every option they use is paid in blood.

Components, Location, and Time

Spell components create investigative work. Some are reusable, such as the great standing stones needed to Call Hastur. Others are consumed, such as space-mead that is drunk. The spell description says which is which; do not assume an item survives because the spell worked once.

A rare component can identify a supplier, reveal a cult's methods, tie a ritual to a place, or force a choice between theft and delay. A reusable one becomes a vulnerable asset: something to protect, something someone else wants, or a clue that exposes the investigators.

Casting time matters as much. A spell may be instantaneous, take a round, a minute, a day, or a week. In combat, an instantaneous spell goes off at DEX+50 like a readied firearm, a one-round spell on the caster's DEX that round, and a two-round spell on their DEX the following round. A one-week ritual has no combat value but can reshape a campaign if the group can hold a safe place long enough to finish it. Location requirements such as underground, a cemetery, or a particular star above the horizon are there to give the group a reason to investigate and prepare, not to deny use.

Read the Cost Before You Roll

Use this table conversation before any serious casting attempt:

1. Read the whole cost line. Magic Points, Sanity, POW, components, casting time, target, and location.
2. Mark current resources. Current Magic Points, Hit Points, Sanity, and any wound or instability that changes the risk.
3. Calculate the ordinary attempt. Work out what remains after the first payment, before rolling.
4. Name the first-cast failure decision. If the Hard POW roll fails, can the group walk away, relearn later, or is a push the only way to get the effect in time?
5. Estimate push exposure. No one needs to pre-roll the 1D6, but everyone should know a failed push multiplies every listed cost and turns a Magic Point shortfall into injury.
6. Assign scene jobs. Someone watches for interruption, someone protects the materials, someone plans treatment or escape, and the caster knows what they are giving up.

A group that has spoken the price aloud can choose to pay it on purpose.

Example: A Cheap Spell That Is Not Cheap

Nora learns a protective ritual that costs 3 Magic Points and 1D4 Sanity. She has 10 Magic Points, 48 Sanity, and a full night before the expected attack, so it looks inexpensive.

The full description changes the decision. The spell takes four hours, needs an object from the threatened household, and only works while the caster stays inside the marked room. The group must get the object without alerting the household's hostile caretaker, protect Nora for the whole rite, and decide what happens if the danger arrives early.

If this is her first casting and she fails the Hard POW roll, the group has lost more than 3 points. It has lost four hours, drawn attention to the room, and left Nora with less in reserve. A push means paying again and risking the 1D6 multiplier. The rite may still be the right choice. It is not a cheap one.

Cthulhu Mythos Knowledge Has a Ceiling

Every source of magic also raises Cthulhu Mythos skill, and maximum Sanity equals 99 minus that skill. As the skill rises, the ceiling on Sanity falls. That is the game saying that deeper comprehension of the Mythos changes an investigator's ability to live comfortably in the world they once knew.

Players should not treat Cthulhu Mythos points as free expertise. The skill helps recognize horrors, recall forbidden facts, and understand what a tome or spell implies, and it records that the investigator paid for those insights. The more interesting question is often whether the character is willing to learn this particular fact now.

Keepers should let Mythos knowledge open avenues without making it a universal answer. A successful roll might identify a ritual's broad purpose, recall a dangerous association, or warn that a familiar solution will fail. It should rarely deliver a complete plan, a safe spell, and a precise enemy weakness at once.

Contact Spells

A Contact spell is an attempt to make something notice you, never a command. The investigator does not acquire an obedient informant; they open a channel to an independent alien intelligence with its own goals, fears, and hungers. That makes Contact some of the most useful and most dangerous investigative magic in the game. The right question can save a campaign. The wrong tone, place, or offer can make the investigators memorable to something they should have left alone.

The one-line rule: never use a Contact spell to ask "What should we do?" Use it when you have one narrow question, one plausible offer, and one exit plan.

Contact Is Not Call or Summon

The Grimoire separates three spell types that all bring the Mythos into a scene:

• Call spells are immense rituals that bring a physical manifestation of a god before the caster. Dismiss spells send it back and may be useful to investigators. Neither is an information-gathering tool.
• Contact spells request communication, which the rulebook compares to an esoteric telephone call. With Mythos creatures, a successful contact draws one or more to the caster, but they come of their own will and are not controlled. With a deity or Great Old One, the spell opens communication without necessarily producing a physical manifestation.
• Summon spells compel a monster, not a god, to appear, and a Bind spell can bend it to the caster's will. Summoning without the ability to bind is a different and usually worse problem.

Do not let the conversational framing make Contact seem safe. A creature that answers may be curious, hungry, insulted, opportunistic, or leading the investigators toward something worse. The lack of control is what makes the meeting a real scene.

Know What You Want Before You Reach Out

The rulebook says the caster should have a definite goal in mind. That gives the Keeper a concrete question to answer and stops a successful spell from collapsing into a vague request for exposition. Good goals are narrow, factual, and tied to the current case:

• "Which of these three symbols marks a safe route through the flooded tunnels?"
• "What does the cult need from the missing surveyor?"
• "What name did the previous caretaker use for the thing in the well?"
• "Will this object attract the same creature that killed Dr. Vale?"

Bad goals are sprawling or hand away the investigators' agency: "Tell us everything about the cult," "How do we win?", or "Will you help us defeat the villain?" An alien intelligence might answer any of them, but the answer will likely be partial, self-serving, or an invitation to a bargain nobody understands.

Write the question down before casting, then decide what an answer would change. If the group cannot name its next action, it should keep investigating until the Contact scene has a purpose.

Creature Contact: An Invitation, Not Control

The general framework for creature Contact spells is a Sanity cost of 1D3, plus any loss for seeing the creature, and a casting time of 1D6+4 rounds. Each spell sets its own Magic Point cost and conditions; Contact Ghoul, for instance, costs 5 Magic Points, and the rulebook's own example lets a moonlit graveyard reduce that to 4. Knowing one Contact spell does not help cast another.

Once properly cast, most creature Contact spells succeed automatically unless none of that species lives within a convenient distance. The spell has reached the species; the encounter is another matter. The rulebook's entries point to likely places, such as mountains the mi-go mine, coasts near deep one cities, or old burial grounds for ghouls, and some add their own requirements, such as an ice effigy and a sung chant.

Arrival may take an hour, a day, or longer. Local entities walk, swim, dig, or fly to the spell point. Things from other dimensions arrive in whatever unsettling way suits them. If the trip is too long, nothing comes. A small species may send several representatives; a large one usually sends one. The rulebook also advises the caster to be alone or with a small group so as not to seem threatening, and notes that the creature is free to leave, so having something to offer makes a longer meeting much more likely.

A late or absent visitor still counts as a delivered invitation; the world and the creature get a say in what comes of it. Choose a location where waiting is possible and where an unexpected arrival will not ruin everyone.

Deity Contact: 5 POW and a Poor Chance

Contact Deity spells are their own category, not pricier creature spells. The standard cost is 5 POW and 1D6 Sanity, with a casting time of 1D6+4 rounds. The caster sacrifices the POW first, then the chance of reaching the deity equals half the caster's reduced POW.

A success does not buy a friendly audience. The deity or some aspect of it responds in a semi-friendly way after a few game hours or days, often through dreams, visions, or nightmares, and it is unlikely to give non-worshipers anything of value. Each version reflects its deity: Cthulhu tends to answer in dreams, Nodens only reaches callers in remote, unpeopled places, and Y'golonac tries to convert the caster.

The rulebook says these spells are used almost only by insane priests and powerful independent sorcerers hoping to strike deals. An investigator considering one should be out of ordinary options, with a reason specific enough to justify permanent damage. "We want answers" is not enough. When it works, it might produce a warning, an impossible demand, or a sign the petition was ignored, and it may start a relationship that outlasts the scenario.

Place, Timing, and Conditions

Contact spell procedures reflect the nature and habitat of the thing contacted, which is why no two of them work alike. A subterranean creature may need a site with recent earthquakes or volcanic activity. A cold-dwelling being may need an ice effigy in a frozen waste. A sea-dwelling intelligence answers at the shore.

Treat those requirements as investigative leads. The group may need to find the right site, get access, work out when it is safe, prepare an unusual object, or travel. That ties the spell to the setting and makes success feel earned.

Timing matters after the ritual too. If an entity may take a day to arrive, Contact is not a last-second rescue. The investigators need somewhere to wait, food, cover, a story for police or locals, and a way to tell when the response has begun. A perfect cave, cemetery, or shore may make the spell possible while also putting the group in the visitor's home territory.

Prepare the Conversation, Not Just the Ritual

A successful Contact spell leads to roleplaying. Prepare the conversation as seriously as the chant. Before casting, decide:

• Who speaks first, and why that investigator is least likely to offend.
• What exact question the group will ask.
• What the investigators can offer: information, an object, a promise, access, silence, or a future favor.
• Which subjects are off limits because they reveal too much, insult the entity, or invite a demand.
• What signal ends the conversation and sends everyone out.

An offer has to make sense from the visitor's side. Money, legal authority, and moral arguments may mean nothing. A creature may value a name, a corpse, a map, a location, a warning, a way into somewhere, or the chance to make the investigators do work it cannot do itself.

The group needs just enough structure that everyone contributes, short of a full negotiation plan. The scholar identifies the creature's likely interests. The detective frames the question. The social character watches for an advantage. The practical character plans the exit when the price gets too high.

When the Answer Arrives

Contact succeeds when communication happens, not when the group gets the answer it wanted. The visitor may inform, question, counteroffer, lie, test the investigators, leave in silence, or arrive only to establish that it now knows who called. The rulebook states flatly that nothing guarantees a contacted entity would rather bargain than devour the caster. Run the encounter in stages:

1. Arrival: A sign that makes the approach recognizable before the full reveal, giving the group a moment to react.
2. Recognition: Sanity rolls for witnessing the entity. The ritual has crossed from theory into fact.
3. Exchange: The group's prepared question and offer. Give the visitor a motive and a limit.
4. Price: Make any demand concrete. A bargain should create a future decision, not an unknowable immediate commitment.
5. Departure and evidence: Tracks, a missing object, a witness, a new dream, a damaged site, or a promise someone must now keep.

The best Contact scenes give useful but incomplete information. The investigators learn where to go but not how to survive there, or identify the cult's real target but owe the visitor a favor.

Example: Asking the Wrong Question Well

An underground creature has been taking workers through the old drainage network beneath a mill town. The investigators have a Contact spell that may reach a subterranean species, and their first impulse is to ask how to kill it. The Keeper asks them to be more precise.

After reviewing their evidence, they ask instead: "Which tunnel leads to the chamber where the workers are still alive?" The question has a clear goal, an immediate next action, and a reason the creature might know.

They choose an abandoned culvert over the town square. One investigator prepares the required condition, one keeps the car running, and one carries a brass case holding a map of a sealed mine entrance. The map is their offer; they will promise nothing more without hearing terms.

The creature arrives hours later. It points to a route on the map, then asks why the town sealed a passage that belongs to its brood. The group has its lead, and a realization: the map records a human effort to keep the creature out of another part of town. They can take the answer and flee, negotiate, or dig into the old sealing operation. The spell moved the case forward without becoming a safe oracle.

Mythos Tomes Are Scenario Tools

The rulebook warns that tomes, like powerful spells, can unbalance a game, and describes them as written by people whose sanity was long gone: no indexes, no tables of contents, sometimes no page numbers or even breaks between words. Obtaining one can be a full scenario, a perilous side objective, or a complication the group has to contain.

Every tome should have an immediate narrative job. It might identify a location, name an entity, reveal a cult's historical pattern, explain a ritual's deadline, hold a partial countermeasure, or make an antagonist hunt the investigators. If it only exists to award points, replace it with a clue and nothing is lost.

Possession should also have consequences. The book may be fragile, stolen, coveted, notorious, or wanted back by someone. It may change how its reader thinks. The group can hide it, hand it to an institution, destroy it, use it as bait, or study it under strict conditions, and each choice creates a different next scene. The Mythos Tomes guide covers translation, reference research, and possession in more depth.

The Tome Study Cycle

Use the same sequence whenever investigators find a Mythos tome:

1. Examine it safely. The Keeper describes the cover, condition, language, annotations, and physical risks.
2. Establish access. The reader can quickly tell whether they know the language. If not, a translator is needed, and the Keeper decides what is translated, how fast, and how accurately.
3. Make an initial reading. The Keeper sets the timing and whether a Language roll is needed.
4. Apply what was learned. The Cthulhu Mythos gain, the Sanity cost for believers, and a bounded sense of the contents.
5. Decide whether to study further. Full study is a long commitment with another cost and possible benefit.
6. Let the tome affect the story. Someone wants it, it points to a new lead, or the reader's relationship with it becomes a problem.

The cycle keeps a book from becoming one opaque die roll and creates natural pauses. The group can secure the book before reading, read only enough to identify the threat, or put off full study until the current case is over.

Initial Reading

An initial reading can be a quick skim or a cover-to-cover read, lasting minutes, hours, days, or weeks as the Keeper wants for the story. The Keeper may grant automatic success to anyone with some skill in the language. Otherwise the reader makes a Language roll at a difficulty set by the book's age, form, and condition: Regular for a book printed within the last century and in good shape, Hard for a handwritten work, especially an old one, and Extreme for the worst moldering tomes mixing print and handwritten annotation.

On a success, the reader gains the tome's Cthulhu Mythos Initial (CMI) value, and a believer automatically loses the tome's Sanity cost, with no Sanity roll. The reader also learns what the book contains, gets some idea of its spells, and knows how long full study would take. The rulebook's example is the Book of Eibon: Sanity loss 2D4, Cthulhu Mythos +3/+8, full study 32 weeks, Mythos Rating 33.

On a failure, the reader gets an inkling of the contents but no Cthulhu Mythos skill and no Sanity loss. The player can push by justifying it, such as staying up all night or using reference works, and a failed push should include Sanity loss. A reader in no hurry can simply keep reading, with the next roll at the Keeper's discretion, perhaps once a week.

Full Study

Full study means reading the whole book properly: repeated passes, comparison with other works, notes. No reading roll is needed; that happened during the initial reading. It can take many months. At the end, a believer rolls the tome's Sanity loss again. If the reader's Cthulhu Mythos skill is below the book's Mythos Rating, they gain the Cthulhu Mythos Full (CMF) value; if it is equal or higher, they gain only the CMI value.

Only one tome can be studied at a time. The weeks need not be consecutive, and the Keeper can shrink or stretch the listed time for the reader and circumstances. Each further full study of the same book takes twice as long as the last, with the same Sanity loss and skill check, so returns diminish. For the Book of Eibon that means 32 weeks, then 64, then 128. A character who keeps returning to the same volume is making a story choice about obsession.

Full study also gives an automatic skill tick in the book's language, and the Keeper may grant a tick or 1D6 to 1D10 points in related skills such as History, Archaeology, Anthropology, Occult, or a science. Keep those benefits narrow and tied to the text.

Example: Study Creates a Decision

Professor Hale finds a tome that may explain the symbol on a drowned victim. An initial reading identifies a contact ritual and shows that full study would take months. The group can use the clue to find the coastal cult now, or Hale can stay behind to study while the others continue the case. The tome matters because it splits the group's effort, risks a mind, and opens a new source of knowledge, not because it solves the mystery.

Languages, Copies, and Handling

Describe a tome before anyone reads it. Language, age, handwriting, missing pages, marginalia, and condition all create research questions. A translation may need to be found, commissioned, or verified. For an unknown or long-dead language, the rulebook says the investigators need a plan that convinces the Keeper, or the book baffles them.

Copies of the same work need not match. The rulebook says each copy can differ from its fellows, and an original-language edition found where only translations were known is more informative, worth a few extra Cthulhu Mythos percentiles. A binding can hide inserted pages, and a previous owner may have left dangerous annotations. Treat those differences as clues and complications.

Many tomes are fragile enough to crumble without thin gloves and padded forceps. A ruined page, an interrupted translation, or a missing annotation can become a new lead. Make preservation needs visible facts that reward care, expert help, or a decision to put the book ahead of speed.

Player Guidance

Treat spells as commitments. Learning one says something about your investigator: what frightened them enough to study it, what they hope to control, and which line they believe they will not cross. That is more usable character material than a list of effects.

Ask the Keeper for the known cost and requirements before you cast. That is not asking for hidden story consequences; it is asking what your investigator could read and prepare for. Fiction-first questions help too: "Would the conservatory give me room for the gestures?" or "Does this need the person present, or only a personal object?"

Keep separate notes for Magic Points spent, Sanity lost, POW sacrificed, and Hit Point damage. They recover differently and mean different things in the fiction.

When you fail a first casting roll, pause before pushing. Consider the threat, your condition, who depends on you, and whether success actually leaves the group better off. If you do push, say why in a sentence. It gives the Keeper something to make the consequence personal and fair.

For Contact spells, bring the Keeper a question, an offer, and a limit, and plan for the delay: where you wait, who keeps watch, and what you do if the visitor turns up at a bad moment. Do not claim control because the spell worked. For Contact Deity, be exceptionally deliberate; permanent POW and a poor chance of a useful answer mean this is never a routine escalation.

When a tome turns up, do not rush to read it because a book feels safe. Ask what language it uses, who can translate it, and whether the scene allows time to study. A book can be worth more as a bargaining chip, returned, traded, or used to expose an enemy, than as another point of Mythos knowledge.

Play the aftermath. A successful spell should not leave your investigator exactly as they were. They may be shaking, burned, more confident, more tempted, or more isolated from people who have not seen what they have seen.

Keeper Guidance

Give each spell and tome a job in the scenario. A book should point toward an answer, deepen an antagonist, expose a deadline, or force a choice. A spell should solve or threaten one specific situation. Do not hand out a broad list of magic because the group found a hidden shelf.

Telegraph known costs honestly. If an investigator can understand that a spell needs 8 Magic Points, 1D6 Sanity, a graveyard, and a night of uninterrupted work, tell the player. Keep the uncertainty in the effect's consequences, the threat's reaction, and the price of a failed push. Horror works better when the group knowingly opens the wrong door.

Tune costs as a package when adapting a spell. The Grimoire says there is no set ratio of cost to effect, and that the source matters: a badly translated, incomplete tome can give a weaker version at a higher cost, while a spell imparted directly by a Great Old One can be stronger or cheaper. A bigger or longer-lasting effect should cost more of something, whether Magic Points, Sanity, POW, time, components, or risk.

Use spell access to create leads. A book points to an old owner, a missing translation, or an organization that wants it back. A teacher demands a favor. An entity's lesson becomes a recurring threat. On a pushed casting failure, honor the effect first, then build a consequence that is immediate enough to matter and lasting enough to affect later choices. Do not reduce every cost to body horror; evidence, obligations, damaged relationships, and lost time often last longer than another nosebleed.

Make the difference between Contact and Summon explicit when players learn a Contact spell. Give contacted entities agendas, but do not make every contact a betrayal; a truthful answer with an uncomfortable price usually drives more sessions than a lie. Use travel time and place for texture: a distant creature that never arrives still tells the group something about the threat. For Contact Deity, protect the size of the choice. Do not reward a POW sacrifice with a campaign-ending solution, but give a result that proves the entity heard.

Limit how many tomes circulate. One volume can carry several scenarios through its provenance, spells, and reference value. If every location has a new tome, books lose their weight and Mythos advancement becomes routine. Use possession for consequences that involve the campaign's existing people and places.

Keep mundane investigation relevant. Magic should reveal a direction, protect a narrow opening, or offer a dangerous shortcut. The group should always be able to investigate, flee, negotiate, sabotage, protect, or seek help, even when a forbidden ritual exists. Magic is frightening because it is not the only answer, even when it looks like the fastest one.

Magic and Mythos Tomes Guide Library

Magic and Tome Checklist

Before anyone casts:

• The investigator has actually learned the spell and believes in the Mythos.
• The spell's requirements, casting time, and Magic Point, Sanity, and POW costs are known.
• Current Magic Points, Hit Points, and Sanity are recorded, and any shortfall is understood as Hit Point damage.
• The caster has room and freedom to perform the rite, and the group has planned for interruption, witnesses, and escape.
• A first casting uses a Hard POW roll; a failure does nothing, and the group can stop, relearn, or push.
• A failed push still works but multiplies the costs by 1D6 and brings a side effect.
• For Contact: the spell type is clear, and there is a narrow question, an offer, a waiting place, and an exit.
• A nonmagical route stays open where the scenario allows one.

When a tome is found:

• Describe its language, condition, provenance, and obvious risks.
• Decide who can read it and whether it needs translation or expert help.
• Set the initial reading's time and difficulty, and make it a meaningful choice.
• Know its CMI, CMF, Sanity loss, Mythos Rating, and full-study time.
• Give the initial result a bounded clue, a cost, and a next decision.
• Treat full study as a long-term commitment, not downtime bookkeeping.
• Let possession create a campaign consequence worth playing.

Where To Go Next

Magic in this game rarely stays contained to a single scene: a costly casting or a dangerous tome usually calls for a Sanity roll next. See the Sanity System Guide for what that costs an investigator, and the Cthulhu Mythos Guide for the entities and cults that hand out spells and books in the first place. For everything else in the collection, the Call of Cthulhu 7e Guide Hub is the index.