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Chthonian is geared mostly for fans of weird fiction, but can easily be modified for other tastes. Central to the game is the concept of the Narrator and Players. The Narrator acts as the author of the Story, describing events and actions taken by secondary characters. Players roleplay the part of Excursionists, the main protagonists of the Story.

When beginning a game of Chthonian it is recommended that the Narrators and the Players are all on the same page. Be sure that everyone knows the Style of play, the themes to be explored throughout, and what their Excursionists are expected to be able and unable to do.

You will notice that there is no Narrator section here. This is because the Narrator needs to know no extra rules outside of Creating an Excursionist and Mechanics. A good Narrator should remember that the Players and the Narrator are creating a Story together, and should encourage suggestions from Players for the Story and allow the Players the full use of their Nodules. This game is designed to be played with several levels of Style. For fans of action-packed adventures filled with goons that drop like flies from a hero's revolver, the Style is Pulp Adventure. If the Excursionists only slightly better than average at dealing with the supernatural and bizarre, it is called a Weird Tale. The grittiest, and potentially most dangerous Style is a Shocking Discovery, where most Excursionists will wind up dead, mad, or somewhere in between. Aside from a pencil and paper, you should have a twelve-sided die, a duodecahedron being the weirdest of the regular polyhedrons. Players use tokens, called Nodules, which can be represented by anything from scratches on paper to pennies to Mancala stones.

It is recommended that you have read some weird fiction appropriate to the Style, in order to play your Excursionist or Narrate to the fullest extent. H.P. Lovecraft is the quintessential author of weird fiction, though there are certainly others [Bibliography & Filmography to come later].

You should come up with your concept together with the other Players, so all of you can create Excursionists that satisfy the group. Your concept can be as complicated or as simple as you like. It is most important that you and the other Players have a feel for who your Excursionist is. If it is important to you or the Narrator, you should write down your Excursionist's friends, possessions and even some history.

My Excursionist is Walter Henning, a journalist working for a reputable local newspaper. Three months ago he traded in his job as a detective so he could get more public recognition as a reporter.

Walter's friends find him a likable guy, though he can be bull-headed over small details. His stubborn nature helps him with his job, but he can be difficult to ignore and comes off arrogant at times.

His motivation to find a good story and prove his ability to the public leads him to join up with the other Excursionists.

Walter lives alone in a small apartment close to the center of the city. While he carries a tape recorder instead of a badge now, he still isn't comfortable without a gun and packs his revolver whenever possible.
Any descriptor in the game, if notable, can be beomce a Trait. A library may have a Well Stocked Trait or a rifle may be Rusty. In the case of your Excursionist, each Trait is something above or below the average ability of an ordinary person. Traits can be a learned occupation, natural ability or any other descriptor, such as Poor or Respected.

A Trait can be good or bad for the Excursionist, depending on his situation. Every Trait has a value which indicates how much it affects the Excursionist. A Trait with a value of 1 or 2 means the Excursionist is somewhat better (or worse) than most people, or a hobbyist in that field; 3 and 4 indicate a professional or a notable skill or detriment; 5 and 6 are reserved for few people; 7 and above are had only by the most extraordinary or unlucky.

Traits are used in the game for easier roleplaying and as modifiers to dice-rolling. By glancing at your own Excursionist's Traits, you have a good idea of what he is capable of and can use these Traits as a framework for in-game development. As the Narrator it is easy for you to write down a few Traits for anything that appears in the game, a condemned building could have Weak Flooring 3 or an automobile could be Speedy 2.

You may give your Excursionist as many Traits with whatever values you want, though the Narrator has the final say on whether to allow your Traits.

Number Description
1 or 2 Hobbyist or a mentionable characteristic
3 or 4 Professionally able or impressive
5 or 6 Nearly unmatched; best of the best (or worst of the worst)
7 and above Seemingly superhuman or astoundingly pitiful

After some thought, and the Narrator's approval, I write down the following:

Walter Henning
    Journalist   2
    ex-Detective   3
    Stubborn   1
Throughout the game, your Excursionist may grasp mind-bending knowledge and encounter insanity-inducing creatures. This will tear at your Excursionist's physical and mental well-being. This measure of knowledge combined with a loss of stability is called Terrible Insight. Every point of Terrible Insight gained gives a point to a pair of special Traits: Practicality and Cognizance. The meaning and values of these Traits depend on the Style.

As Narrator, you decide how Terrible Insight affects the Trait values. This should depend on the Style and your personal goals. Suggested Trait values are given below.

Terrible Insight & Style
Style Trait Suggested Value* Description
Pulp Adventure Practicality One-third Terrible Insight Your Excursionist favors direct methods over the sociably-conscious ways of a proper gentlemen. His manners and dress are often at odds with the upper class, placing practicality above style.
  Cognizance One-half Terrible Insight Recognizing ancient cultures, their languages and practices, becomes intuitive. Weird science bends thinking less as your Excursionist recognizes the bizarre logic which applies.
Weird Tale Practicality One-half Terrible Insight An Excursionist with an increased Practicality will lose sight of his social peers' mores, discarding the trappings of culture and society.
  Cognizance One-half Terrible Insight Making sense of mind-bending logic and the motivations behind darker cult practices.
Shocking Discovery Practicality Equal to Terrible Insight In a Shocking Discovery, a character's Practicality affects his ability to interact with ordinary people and think in a logical manner.
  Cognizance Equal to Terrible Insight With sanity crumbling away comes understanding of the true mechanics of the universe. Your Excursionist suffers from a heightened understanding of weird science and otherworldy entities.
    * Round down to nearest whole number.

At the beginning of each Story, you receive a number of Terrible Insight Nodules equal to your Excursionist's points of Terrible Insight. These can be spent to affect different aspects of play from the outcome of a die roll to adding your own events to the Story. Details on using Nodules and the price your Excursionist pays is given later in the Mechanics section.

Excursionists never have to be taken out of play, no matter how high their Terrible Insight, though a Player is encouraged to retire their character and create a new one if the Excursionist interferes with the Story. Pulp Adventures do not cause too much harm to Excursionist, a hero may be disgruntled by their effete sponsors but stories of adventure and the treasure that follows will always speak louder than niceties. Weird Tales cause the Excursionist more trouble, distancing the character from his peers no matter what their social class. The worst effects are to be had during a Shocking Discovery, where insanity is the inevitable result of Terrible Insight.

It is easiest to record your Terrible Insight right along with your Practicality and Cognizance, as shown in the example below.

Walter begins with no points of Terrible Insight. His experience as a detective has been limited to mundane crimes of the city. I mark a place to record Walter's Terrible Insight. For each point of Terrible Insight I will check off one of the O's.

Since the Narrator and Players have decided to play a Weird Tale, my Numbers in Practicality and Cognizance are equal to one-half my Terrible Insight rounded down.

Terrible Insight


-1 -1 -2 -2 -3 -3 -4 -4 -5 -5
 O  O  O  O  O  O  O  O  O  O
+1 +1 +2 +2 +3 +3 +4 +4 +5 +5

Your Excursionist will try and do many things throughout the game. Many of them, such as walking across the street or calling someone on the phone, should be automatic and introducing a chance of failure would slow down the Story. Each Narrator will have her own idea of what actions should be given to chance or automatically allowed and disallowed. For an action that the Narrator feels is automatic, the decision is made and the Story moves on. If an element of risk is involved, the Narrator will often require you to make a Roll. Making a Roll is a fairly simple task. The Narrator tells you the Difficulty of the task, in the form of a number. You roll your twelve-sided die and add or subtract any Traits that apply. Subtract the Difficulty from this number to get the Extent of the Roll. If the Extent is zero or greater, your Excursionist succeeds. A negative Extent usually means a complete failure, but may be an incomplete success. See Further Effects of Extent below for how to apply Extent to game mechanics. The most important value of Extent is as a narrative tool to allow the Narrator to gauge success and further the Story.

Difficulties for Rolls depend on the Narrator's goals. Assigning a specific Difficulty is not so important as furthering the Story and providing an exciting chance of failure. Eight makes a good average Difficulty; add or subtract three from that to provide a tougher or easier challenge. Remember that any Roll is modified by all the Traits at hand, so an Excursionist (Burglar 2) picking a lock (Well-made 1) would apply those Traits to his Roll and not the Difficulty.

If a Player wants to modify her Roll with Traits that the Narrator doesn't think applies, the Narrator can flat out deny the Trait's use, or increase the Difficulty to keep the Player unaware that their Trait doesn't apply. Similarly, if the Narrator wants to secretly allow an Excursionist's Trait to apply, she can lower the Difficulty without alerting the Player.

This is the simplest form of a Roll, called a Standard Roll. There are other methods of rolling, all involving rolling a dice and modifying that roll with Traits.

Types of Rolls
Roll Method Example
Standard Narrator declares Difficulty.
Roller's Extent must be zero or greater.
Opening a stuck door,
Researching an artifact's history
Contest Challengers Roll.
Highest result succeeds in the task.
Outcome of a combat,
Battle of wits,
Snatch a book from a pedestal
Difficult Contest Narrator declares Difficulty.
Every competitor rolls.
Highest Extent greater than zero succeeds
First to solve a puzzle
Cooperative Like any Roll above.
Narrator decides highest Trait.
All other Traits usually give a +0 or +1.
Moving a granite slab,
Linking hands to keep standing

Walter is trying to get into a locked chest. I want Walter to pick the lock using his Ex-Detective Trait. The lock is Well-Crafted 3 and the Narrator doesn't think Walter's Trait applies. She decides that picking the lock would be a Standard Roll with a Difficulty of 11. I roll an 8, adds Ex-Detective 2 and subtracts the lock's Well-Crafted 3 for a result of 7. My Extent is -4 (7 minus 11). Walter fails, nicking his finger in the process.

Walter then takes a more direct approach and grabs a crowbar. The Narrator wants to add the element of chance to this (the chest is fairly tough) and requires a Roll. The Narrator says it is a Standard Roll with a Difficulty of 5. Walter' Player rolls a 7, adds the Crowbar's Pry 2 for a result of 9. My Extent is 2 (9 minus 7). Walter opens the chest and finds a mysterious jade figure inside ...

Rolling: Contest Roll
A Contest Roll is made when characters or forces are attempting to complete the same action, or are opposing each others' actions. For this to be a Contest success or a tie must be guaranteed. If there is the possibilty of failure by all parties, it is a Difficult Contest described below.

In a Contest Roll, the competing forces make a Roll modified by their Traits. A Trait should be applied only once in the Contest Roll. If an Excursionist (Athlete 1) is outrunning a policeman (no applicable Traits), the Athlete Trait will apply to only one die.

The higher result accomplishes the task, the difference between the two results is the Extent. If there is no higher result, the Extent is zero and neither character wins. If one character must succeed, keep rolling until there is a success. As Narrator, you are encouraged to use this Extent as explained in Further Effects of Extent below.

If one force must succeed, and the results are tied, the force with the highest Trait (or combination of Traits) wins. If all Traits are the same, the Contest Roll should be rerolled. Narrators and Players are encouraged to describe the Story events that cause this reroll.

A bizzare creature identified in Phinnias' Bestiary as a Grumbling Mulk swings its hairy paw at poor Walter. The Narrator makes this combat a Contest Roll. Walter is using his revolver (Powerful 1) and is an Ex-Detective 2. The Mulk can be described as having Inhuman Strength 3 and Tough Hide 1.

I roll a 6 and add Walter's Traits for a result of 9. The Narrator rolls an 8 for the Mulk and adds the Mulk's Traits for a result of 12. The Mulk is the winner with an Extent of 4 (12 - 8). The Narrator tells me that the Mulk's furry paw smacks Walter's head like a sack of bricks, sending poor Walter flying against a wall.

Walter creeps into the room to spy his jade figure on a table. A hooded man appears in the doorway and shouts, "The Goddess is mine!" The pair race towards the table. The Narrator gives Walter a Trait Close to the Jade Figure 2 (only for this instant). I roll a 6 (4 + 2), not enough to beat the Narrator's roll of 10! Walter's jade figure disappears into the man's loose robe.

Rolling: Difficult Contest Roll
When more than one force is competing for the same outcome, and a winner is guaranteed, it is a Contest Roll. Each acting force makes a Roll, and the highest result succeeds at the task.

If there may not be a winner, then it is a Difficult Contest Roll. Each participant makes a Standard Roll against a Difficulty, and the character with the highest Extent also greater than zero succeeds. If no Extent is greater than zero, nobody completes the action.

Rolling: Cooperative Roll
Any Roll where multiple characters can join their ability is called a Cooperative Roll. This means that the Roll proceeds as normal, but all cooperating characters' Traits modify the roll. The Narrator should determine how the Traits will modify the roll.

For most tasks The Trait with the highest Number Trait uses that Number in full, and every other helpful Trait adds 1 to the roll.

Other cases must be judged as they occur. Some actions are hampered by the weakest link, so the Narrator would choose the worst Trait as the only modifier. Other actions are helped by every single person, and the Narrator would add each character's Traits to the roll.

A sturdy chain leads down into a murky lake. A single Excursionist could try to pull it up, but all the characters are going to pool their strength and pull up the chain together. The Narrator decides to add up all strength-related Traits, and any Traits that would normally hinder the roll are not applied.

The four Excursionists all have covert operation backgrounds and work on a strategy to infiltrate a scientific compound. The Excursionist with the highest Trait (in this case an ex-Green Beret 4) applies the Trait in full, and everyone else planning adds 1 to the Roll.

Rolling: Further Effects of Extent
While a simple Extent of zero or greater indicates success, there are times when the Narrator and Players want an actual measure of success. Did the bullet graze the cultist, or is it buried deep in his gut? The simplest way to handle this is to use the Extent as a new Trait. If the Extent is something that causes damage, for example, the victim receives a Wounded Trait equal to the Extent.

In some cases, where the Extent is negative and would imply a failure, the Narrator may decide the Roll succeeds but the Extent applies a Trait the success. Forging a painting and getting a negative Extent may give the painting a Poor Copy Trait, for example.

The Style of the game should affect the effects of Extent, since a Pulp Adventure shouldn't have an Excursionist crippled by a faceless thug's lucky stab. When an Extent creates or modifies a Trait beyond the conventions of the Style, the Narrator should feel free to increase or decrease the Extent.

Examples of Style & Extent in Combat
Style Situation Extent
Pulp Adventure Damage from Faceless Goons & Traps One-fifth Extent
  Damage from Main Villain One-half Extent
Weird Tales Mental Damage One-half Extent
  Phsyical Damage Full Extent
Shocking Discovery Any harm to Excursionists Full Extent

Walter writes down some complicated directions on opening the secret compartment in his jade figure. I make a Roll with an Extent of 4. The directions now have the Trait Instructive 4. Anyone trying to decipher Walter's notes would add the Instructive Trait to their own Roll.

Undaunted by the fearsome Grumbling Mulk, Walter fires his Revolver (Trait: Powerful 1). I Roll successfully with an Extent of 3. The Mulk is now suffering from a Wounded 3 Trait, and applies the new Trait to all its future rolls.

Some players may want to add further detail to their Rolls, called Atomizing in Chthonian. When Atomizing, a task may be split into multiple Rolls, and Traits may modify only the Roll or the Extent. Splitting a task is simple, one Roll is made to accomplish part of the task, another to complete the next part, and so on (possibly using the Extent of a Roll to modify later Rolls). When Traits modify either the Roll or the Extent, the Player should roll the die, using any Traits that would modify the Roll to figure the Extent. Only if this initial Extent is a success does the Player add Traits to the Extent for a final result.

Atomizing a Roll is most often used in combat, where the speed of the attack determines a successful hit and the strength of the weapon adds to the Extent.

The Narrator and Players have agreed to Atomize any combat Rolls. Walter, wearing a protective vest (Protection 1) faces a Phase Bear (Strong 3, Clumsy 1). The Phase Bear lunges at Walter. Walter tries to duck and I roll a 7 (no Traits apply). The Narrator rolls a 9 (10 - 1 for the Phase Bear's Clumsy) for an initial Extent of 2. Traits are then used to modify this Extent, so the final Extent is 4 (2 + 3 - 1 from the Bear's Strong and Walter's Protection).

Walter, snooping around a warehouse, surprises a band of cultists who immediately begin shooting! Walter wants to dive for cover while firing at the cultists. This would normally be one Roll but the Narrator decides to Atomize the Roll. I must make a successful Roll to dive behind the crates and not get hit by gunfire, and a separate Roll to hit any cultists.

Each Excursionist has points of Terrible Insight. When the Player must make a Roll requiring success in stuffy social circles or a partially-sane understanding of non-Euclidean travel, the Roll is modified by two Traits: Practicality and Cognizance. Terrible Insight not only affects these Traits, but provides a Player with Nodules of Terrible Insight for use during play. Both the Traits and Nodules are discussed in this section.

Whenever an Excursionist encounters some bizarre otherworldly monster or studies some erudite partial manuscript, the Narrator may ask for a Standard Roll at some Difficulty (determined by the Narrator). The Roll is modified by the Excursionist's Practicality, failure gaining a point of Terrible Insight. Conversely, when the Excursionist gains a foothold on practical and social matters by interacting with proper company, the Narrator may request a Roll to lose a point of Terrible Insight. When to make these Rolls and how many points are gained and lost is entirely up to the Narrator.

If the Excursionist is lucky enough to receive mental treatment or somehow forget their horrific experiences, they may make a Standard Roll at a Difficulty determined by the quality of the treatment. This Roll is also modified by Practicality. Notice that the more Terrible the Excursionist's Insight, the tougher it is to resist madness.

Points of Terrible Insight gained or lost during a Story do not affect the Player's current amount of Nodules. It is entirely possible for a Player to have more Nodules than points in Terrible Insight, or vice versa.

A Player receives as many Nodules as her character has points of Terrible Insight at the beginning of each Story. These Nodules can be used at any time during play (unless the Narrator denies) and may have one of the effects described below. Using a Nodule comes with a price, the cost described in each method of Nodule use.

Using Nodules of Terrible Insight
Use Description
Automatic Success Player decides Extent of Roll without having to roll the die.
Authorial Power Player writes her own event or character into the Story.
Lucky Break Player causes another character in the game to make a Roll or suffer decided effects.
Insightful Shift Player shifts the focus of the scene towards Practicality or Cognizance.

Walter studies a three volume set written by Ezekial Strium, Wicked Energyes and Their Terrible Uses. After discerning the use of his jade figure to collect ethereal wisps the Narrator decides that a Terrible Insight Roll must be made with a Difficulty of 8. Walter already has a Terrible Insight of 2, and Walter's Player rolls a 7 (9 - 2 from Practicality) for an Extent of -1. Walter gains another point of Terrible Insight.

Using a Nodule: Automatic Success
If you want your Excursionist to automatically succeed at a task, you may spend a Nodule to do so. You then declare the Extent of your Roll as if you actually rolled that amount. Immediately after your Excursionist's success, the Extent you chose becomes a Difficulty for a Standard Roll. In a Pulp Adventure, the Difficulty is half your Extent, a Weird Tale is equal and a Shocking Discovery is double the Extent. This Roll is modified by the Practicality Trait (and any other of the Narrator's choice). Failure gains your Excursionist one more point of Terrible Insight.

Once again, Walter faces a Grumbling Mulk. He still bears scars from his last encounter and is determined not to suffer again. Walter fires his revolver, praying that the knowledge gleaned from Phinnias' Bestiary will aid him. The Mulk, as Defender, rolls a 10. Walter's Player, not wanting to fail, spends a Nodule to get an Extent of 15. The Grumbling Mulk is now completely incapacitated by an amazing shot to its central nerve-bundle.

Walter's Player must now make a Standard Roll with a Difficulty of 15, modified by his Practicality; the Player rolls a 5 (7 - 2) for an Extent of -10. Walter gains another point of Terrible Insight along with new Numbers for his Practicality and Cognizance Traits.

Using a Nodule: Authorial Power
By spending a Nodule you may insert your own event or character into the Story, With the approval of the Narrator, you can cause a single event (that does not immediately call for a Roll), or bring in a single character of your description. If you decide to introduce a character, you should immediately write down a quick description and a list of Traits, modifiable by the Narrator. Remember that the Narrator can choose to deny your Authorial Power if she wishes, but this should only discourage a dues ex machina situation that saves the proverbial day.

When you use your Authorial Power, you must make a Standard Roll modified by your Practicality Trait. The Difficulty is decided by the Narrator, the game's Style, and how helpful your insertion is to you and the other Excursionists. In a Weird Tale, a minor item such as a broken lock, or an overly-generous shopowner gives a Difficulty of 5. Something severe, like an earthquake that opens dangerous cracks in the floor, or the appearance insanely loyal, well-armed soldier would proabably have a Difficulty of 11. These Difficulties may be halved for a Pulp Adventure, or possibly doubled in a Shocking Discovery. Even though the Authorial Power is successful, failure at this Roll gives your Excursionist another point of Terrible Insight.
Using a Nodule: Lucky Break
You are trapped in an alley unarmed, and a cultist is slowly advancing with a terrible knife in hand. This Excursionist could use a Lucky Break! A Lucky Break causes another character grief in the form of a Roll to avoid harm. As the Player, you spend a Nodule to decide the cause of the Lucky Break and the Difficulty of the Roll.

Once the Roll is made you must make a Standard Roll against a Difficulty dependant on the game's Style. Failure gains your Excursionist a point of Terrible Insight. A Pulp Adventure provides a Difficulty half that of your victim's Difficulty, the Difficulty for a Weird Tale is equal, and a Shocking Discovery doubles this.

Using a Nodule: Insightful Shift
This last use of a Nodule can provide for a very interesting roleplaying experience. When causing an Insightful Shift the Player must declare whether he is shifting events towards Practicality or Cognizance. If the shift is towards Practicality, the reality of the scene bends towards the practical and conventional side. A quasi-dimensional hound may become a slavering mastiff, for example. A shift towards Cognizance will increase the weirdness of the situation. If your Excursionist is trying to convince the police that the hound is otherworldly, the thing may enter the police station by way of dimensional shifting.

A shift towards Practicality automatically causes the loss of a point of Terrible Insight. This may be a boon for the Excursionist, but remember that a truly bizarre scene may only shift part of the situation. The Narrator is encouraged to only shift parts of reality where she feels appropriate. Likewise with shifting towards Cognizance: The Excursionist immediately gains a point of Terrible Insight and incurs the mixed-blessing of the gain.

The Narrator may deny Insightful Shifts outright but it is advisable to allow them for the sake of an interesting story. Remember as Narrator you have the ability to apply the shift as dramatically or slightly as you wish. An Player who spends a fair amount of Nodules at one time to shift many pieces of a scene must accept the consequences.

Having discovered a crate filled with tentacles that reached out towards him, Walter is fleeing desperately from the warehouse. As the Narrator describes the wet slopping sounds from behind Walter, I feel this would be a good time to make an Insightful Shift towards Practicality. I spend a Nodule, lose a point of Terrible Insight, and Walter keeps running. Is is eventually overtaken by the sounds, but instead of the horrid thing Walter feared, the sounds were Walter's crazed imagination distorting the rain and cultists' pursuing footsteps.

Later, when Walter hears the sounds once again, I decide to make an Insightful Shift towards Cognizance. I feel that Walter could use an edge against whatever eldritch being is stalking him. I spend a Nodule, gain a point of Terrible Insight, and now Walter's mind is better armed at truly understanding the approaching thing.

Paul Czege: The wonderful idea for Insightful Shift.
Jared Sorenson of Memento Mori fame: Giving me the bug to write a Narrative Lovecraftian game.

Hephaestus' Forge Forum: The indie gaming forum that got me really thinking about RPGs. June 2001
  • Wrote game to promote a narrative weird fiction game, with two major goals: 1. Replace the fear of character death with a sense of curiosity and adventure. 2. Provide rules that support telling a story over a "Library/Crypt Crawl".
  • Removed Qualities from Traits. Realized they were a holdover from tradition "fair" gaming, where you typically have so many points to divide among attributes.
  • Changed Challenge Roll so that whoever rolls highest wins and their Extent applies. I was too stuck in the "I roll to hit you, you roll to hit me" combat style. Using the new method, a combat is resolved with ONE roll of the die per player. Atomizing will cover splitting it up if people want attacker/defender or chance to hit/chance to damage splits.
  • Added the Insightful Shift rule, brought on by Paul Czege. I hope my rules and examples capture our joint thoughts on this.
This entire document and all contents is Copyright © 2001, by Zak Arntson. Permission to duplicate for personal use and captions for review purposes is granted. You must receive explicit permission from the author (email: to use this game and any portion therein for public use, such as publication or convention play.

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