Diabolox – Urban Horror for the Cepheus Engine (with character sheet)

Michael Brown publishes a prodigious amount of stuff for the Cepheus Engine, mostly a lot of one page adventures.

My favorite works of his are his one-page setting guides, mostly based on somewhat obscure sci-fi and fantasy properties. I’ve posted quite a bit about my appreciation of his Omega 99 setting, based on the 1970s Space: 1999 TV show.

Recently, I’ve been playing around with Diabolox, an urban horror setting based on the obscure 1970 horror movie Equinox. (Youtube trailer)

The game’s premise is based around the existence of an evil book. The Book confers power upon its possessor, but also causes them corruption and bad luck.

The book is being pursued by an evil cult, and a mysterious Stranger who may be the Devil himself.

Diabolox is only a one-page setting, so it might require some expansion on the GMs part. Here’s some of the rules and setting additions I’ve been playing around with. I’m assuming Cepheus Deluxe rules.

New Rules


Anyone in possession of the Book gains one Corruption point per day. Casting spells from the book also caused Corruption. When they reach a Corruption level equal to 3 x END, they have to start rolling on the Corruption table. They have to roll again for every multiple of END. This is mostly taken from Sword of Cepheus.

Corruption Table

11 The laws of probability have turned against you – You may no longer roll at advantage, for any reason.
12 Arthritis wracks your body. Reduce DEX by 2
13 All your teeth fall out. Suffer DM-2 to all Reaction and social-skill throws.
14 You are plagued with flatulence.
15 Your essence is corrupted. Dogs and cats sense this, and will attack or flee on sight.
16 Your legs stiffen and ache. You can only move at half speed.
21 Dark sorcery has left you disfigured, with misshapen limbs, clawed hands and feet, strangely colored eyes, and so on. You suffer DM-2 to Reaction and social-skill throws.
22 You begin to stutter. Suffer DM-2 to all Reaction and social-skill throws. At the Referee’s option, this may also impose DM-1 to spellcasting throws.
23 You develop a mild allergy to one common substance chosen by the Referee (such as milk or dog hair). You sneeze uncontrollably or break out in hives while in presence of this substance, suffering from DM-1 to all actions until you are no longer in its presence.
24 Meddling in dark lore has left you with an inhuman demeanor and personality. Your Reaction rolls can never achieve a Friendly result.
25 You grow forgetful, your mind filled with dark lore. Reduce your EDU characteristic by 2, to a minimum of 1.
26 Your demonic demeanor and appearance will cause pious persons to denounce you. Reduce your SOC characteristic by 2, to a minimum of 1.
31 You haunt the night as a creature of darkness; you tend to sleep during the day and suffer DM-1 to all throws when in sunlight.
32 You tremble as dark thoughts course through your mind and body. Reduce your DEX characteristic by 2, to a minimum of 1.
33 Your skin rots; you take on the appearance of a corpse. Suffer DM-2 to all Reaction and social-skill throws.
34 Alien thoughts cloud your mind. Reduce your INT characteristic by 2, to a minimum of 1.
35 You become a predatory being; only fresh, raw meat can sate your hunger. Preserved or cooked meat will not suffice.
36 Your exploration of sinister sorcery has sapped your soul of vigor. Reduce your END characteristic by 2, to a minimum of 1.
41 Your flesh rots and become unholy. You suffer double damage from silver weapons.
42 Whispers from beyond haunt you. You suffer DM-1 to initiative and surprise rolls.
43 Whenever you cast a spell, you emit darkness, as per the spell, centered on you.
44 Your muscles atrophy. Reduce your STR characteristic by 2, to a minimum of 1.
45 You are repelled by garlic; in the presence of garlic, all your throws are at DM-2.
46 Your corruption is unsettling to animals; dogs bark in fear when you arrive. You suffer DM-3 to Reaction throws vs. animals. If you have the Beast Friendship Trait, it now only works with wild predators and scavengers, such as wolves, jackals, and rats.
51 After you cast any spell, your body cools and becomes as cold as a corpse; you suffer DM-2 to all physical throws (which, naturally, does not include spellcasting) for 1D rounds afterwards.
52 The full moon calls for you. Once a month, at a time determined by the Referee, you must throw END 8+ or be overcome with a murderous rage for 1D rounds.
53 You immediately age by four years. Throw on the Aging table if necessary.
54 You grow the horns of a devil! You may cause 1D damage by head-butting, but your devilish appearance causes you to suffer DM-2 to all Reaction and social-skill throws.
55 Your body rots with dark energy and takes twice the usual time to heal (2 hours to heal from minor wounds with treatment, 2 days for healing minor wounds without treatment, 10D days for healing serious wounds with treatment).
56 You begin to lose grip with reality. Each day, upon waking throw END 6+ or go insane for 1D hours
61 You grow a forked tongue. You suffer DM-2 to all Reaction and social-skill throws.
62 You emit the stench of evil! You may never surprise creatures with a keen sense of smell.
63 You gain low-light vision, but your eyes now resemble those of a predatory cat; You suffer DM-2 to all Reaction and social-skill throws.
64 You develop the skin of a frog; you must immerse yourself in water for at least an hour each day or be Fatigued for the next day.
65 You are haunted by nightmares from beyond the grave and find it difficult to sleep. Each time you attempt to sleep, throw 1D; on 1, you cannot sleep; you are Fatigued for the next day.
66 You grow vampiric fangs and can only sustain yourself from the blood of other sapient beings. You must drink blood (cause 1D damage) from one person per day to sustain yourself, in lieu of food. This can come from a willing donor, or from hapless victims (a resisting victim requires a Grapple). Other than that, you do not need to eat or drink.

Bad Luck

Possessing the Book causes ill fortune. Each day there is a 2 in 6 chance of Bad Luck. If you roll a one or two on a 1D, roll once on the Bad Luck Table. The Referee may want to roll, and keep the result secret until the bad luck occurs.

Bad Luck Table

Roll D66
11 Financial Setback – You lose half of your savings
12 Feel the Heat – A law enforcement agent starts hassling you.
13 Engine Trouble – If you have a vehicle, it breaks down at the worst time
14 Where Am I? – Wherever you go, you’ll get lost. GPS will not help.
15 Stormy Weather – The most inconvenient possible weather occurs.
16 Fly like a Butterfly – You have been stung by a bee
21 Dead Man Walking – You’ve been declared legally dead.
22 Can You Hear Me Now? – You lose your phone.
23 Flat Tire – Your shoes will not remain tied
24 My Aching Head – You have migraines all day, DM-2 to all rolls
25 Blue Screen – Your computer crashes, losing all data
26 Does This Taste Funny? – You get food poisoning – DM -1 to all rolls for 2 days
31 Pocket got Picked – You lose your wallet.
32 Message From Above – You are struck by lightning. 5D damage
33 Hives! – DM-2 to all Reaction rolls
34 Attack from Above – A pigeon will defecate on you
35 Bad Meme – You become a figure of fun on the internet. DM -2 to all Reaction rolls for a week.
36 It Wasn’t Me – You have been accused of a crime, falsely.
41 You Seem Quiet Today – You suffer from severe laryngitis, and cannot speak for 1D days.
42 Day of the Animals – You will be barked at, hissed at, and harassed by all animals, wild or domestic.
43 The Flood – Your home, hotel room, or vehicle sustains water damage. All of your stuff is water logged.
44 The Fire – One building you are in today will be set ablaze.
45 Voice From the Past – Someone from your past, who you really don’t want to meet, shows up.
46 Dental Illness – You have crippling tooth pain. -2 DM on all rolls until you see a dentist.
51 Running Late – You will be a half-hour late to everything today.
52 The Visitor – A cultist has found you.
53 Murphy’s Law – Roll at disadvantage for everything today.
54 Where Did I Put Them? – You lose your car keys or some other important item. You’ll find it tomorrow.
55 Bad Doppelganger – You have a striking resemblance to a local lowlife. Today everyone’s going to mistake you for him.
56 Bad Hair Day – No matter what you do, your hair is a mess. DM -1 to all Reaction rolls
61 Soaked – You’re going to get soaking wet. Falling into a pool, splashed by a car, spilled beer etc.
62 Cruising for a Bruising – Someone’s going to start a fight with you.
63 Muckraker – A local reporter is insistent on investigating you.
64 Tummy Trouble – You’ll have an upset stomach all day, and cannot eat anything without vomiting. -2 to END all day.
65 Misplaced Manual – The Book goes missing.
66 Dark Arrival – The Stranger has found you.

Fear Check

When encountering anything occult or otherworldly, players can make a Fear Check. The Difficulty of the roll is to be determined by the GM. The Social DM or Occult skill can be used for this roll. If failed, the character is frozen in fear for 1D rounds. If they fail by 4 or more, they must flee the scene if possible.


Ivory Tower: +2 to social rolls (i.e. Admin, Liaison) at any university
Grim Portent: +2 initiative vs supernatural threats
Cop Face: You get an advantage in any rolls talking to law enforcement
Dead Inside: Does not need to make Fear Checks


The Magic skill can be used to cast certain ritual spells. If the user has access to the Book, they automatically have the skill Magic at 1. The following are spells that can be found in the Book. Casting any of them will give the caster at least one Corruption point.

To cast any spell, make a Magic roll. The difficulty is 8+, unless the spell state otherwise. If the spell fails, the caster cannot try again until the next day. The corruption Each spell takes about a half-hour to cast.

Critical Failure: If the players rolls a natural two ( a one on both dice), something terrible will happen. If the referee can’t decide on what, have the player roll on the Corruption table.

Blood Sacrifice: If the ritual is combined with a blood sacrifice, the difficulty is lowered to 6+ (or one lower level). This will incur a extra cost of 4 Corruption.

Spell List

The following is an incomplete list of spells that can be found in the book.

Windfall: The caster will come into money. The difficulty of the spell is determined by the amount of money gained. The money will appear as a bank error, lucky inheritance, or simply finding a bag of money.
Corruption: 1
2D hundreds of dollars – Magic 6+
2D Thousands – Magic 8+
6D Thousands – Magic 10+
1D Millions – Magic 12+

Curse, Minor: Cause a target to roll on the Bad Luck table. Requires a DNA sample. A lock of hair will do.
Corruption: 1

Curse, Major: The target must roll on the Bad Luck Table once a day for a week. Requires a DNA sample. A lock of hair will do.
Corruption: 3

Sicken: The target will take 1D damage per day. The damage will not heal unless the spell is lifted.
Corruption: 4

Summon Demon: Use the demon rules from Diabolox to create the demon that is summoned. If the Magic roll is successful, the caster can control the demon for 1D hours before it returns to Hell. If the roll fails, the demon will attack.
Corruption: 5

Fade: Avoid the attention of the authorities or pursuers.
Corruption: 3

Seek: Finds the location of any person or object.
Corruption: 1

Knit Flesh: Heals 2D6 damage.
Corruption: 1


Any of these might make good organizations for the players to be a part of, or as encounters.


A website and zine about urban legends & myths. Their correspondents roam the country collecting stories and tales. They’ve heard of the legend of the Book.

Institute for Western Post-Occult Studies

An academic fellowship, with wealthy private backers. Publicly, they claim to be studying folklore, but privately they know of the Book’s true power, and seek to find and understand it.

The Wylde Foundation

A private think tank owned by billionaire financier Winston Wylde. He’s dying, and believes finding the Book is his last chance at survival.


Endurance 10 Lifeblood 20
Gun Combat 1, Melee Combat 1, Streetwise 1

The Stranger
Endurance 40 Lifeblood 80 Armor 4
All skills 3
Can cast any other spells from the Book

Character Sheets

As is my custom, I’ve created a custom character sheet for Diablox. It’s fillable and you can add an image by clicking in the center of the pentagram. I’ve added it to my ever expanding list of character sheets.

***Update 1/24 – Fixed the misplaced Social label on both sheets

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s