OUROBOROS
OSR
OUROBOROS
OSR
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Ouroboros OSR is released under a Creative Commons 4.0
International Share-Alike license. Text is copyright Sean F. Smith ©
2021, with additional text from David Blandy, Panny Lines, Robert
Teszka, Vanessa Thompsett © 2020. Layout by David Blandy. Art by
Daniel Locke.
Structural influences are David Black’s The Black Hack 2e, Luke
Gearing’s Gradient Descent, Homebrew Homunculus’ blog, and
Steve Jackson and Ian Livingstone’s Fighting Fantasy gamebooks.
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OUROBOROS
Four years ago, the folk hero Rico discovered that every dun-
geon in the land was connected — if you went deep enough.
A month later, she set off with a crew of divers to find what
was at the bottom. She was never heard from again.
That is, until this week.
Rico's face appeared on every polished surface in the land and
her echoing voice spoke to us:
"I found something. Come see."
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What’s this?
Ouroboros is a tabletop roleplaying game that espouses Old
School Rhetoric. Players make almost all the rolls and the
Referee presents an environment that's ripe with adventure.
It's compatible with modules produced for the original rpg.
The Core Mechanic
Players roll 1D10 equal to or lower than their score being test-
ed. Rolling a 1 always succeeds; rolling a 10 always fails.
Monsters don't roll for tests.
Modifying rolls
Specialisations or situational details may give advantage on
a test. In these cases, roll 2D10 and choose which one to use.
Other situations may incur disadvantage on a test. In those
cases, you roll 2D10 and the Ref chooses which one to use.
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Powerful opposition
When players act against monsters of a higher level than
themselves, this level is added to the dice roll of all tests made.
If the monster is of equal or lesser level, nothing is added to
the dice roll for the test.
The same rule applies when dealing with environmental
factors above your level. For example, a level three player
trying to memorise a spell of 7th level adds 7 to the LUCK test.
Roll stats
Roll 2D6 in order for the following stats: SKILL, STAMINA,
and LUCK.
If you would prefer not to roll, you may instead assign 20
points between them.
A score of 5 is human average.
Choose specialties
For each stat you have that's lower than 10, choose an area of
specialisation. These take the form of verbs. When you per-
form tasks you are specialised in, you gain advantage on your
tests.
For example:
1. killing
2. hiding
3. waiting
4. remembering
5. seeking
6. reassuring
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BUY EQUIPMENT
Characters start with 2D6×15 gold pieces. Use this to buy
equipment.
Pricelist
Weapons Armour
Melee weapon 10 gp Light armour 10 gp
Ranged weapon 25 gp Moderate armour 100 gp
Ammo (24 shots) 5 gp Heavy armour 500 gp
Shield 10 gp
Objects
Acid (vial) 25 gp Alcohol 1 gp
Antitoxin (vial) 50 gp Backpack 2 gp
Ball bearings 1 gp Barrel 2 gp
Basket 1 gp. Bedroll 1 gp
Bell 1 gp Blanket 1 gp
Book 25 gp Bottle, glass 2 gp
Bucket 1 gp Caltrops 1 gp
Candle 1 gp Case, map or scroll 1 gp
Chain (3 metres) 5 gp Chalk (12 pieces) 1 gp
Chest 5 gp Clothes, common 1 gp
Clothes, fine 15 gp Clothes, traveler's 2 gp
Crowbar 2 gp First aid kit 5 gp
Fishing tackle 1 gp Flask or tankard 1 gp
Grappling hook 2 gp Hammer 1 gp
Holy water (flask) 25 gp Hunting trap 5 gp
Ink (20g bottle) 10 gp Jug 1 gp
Ladder (3 metres) 1 gp Lamp 1 gp
Lantern, bullseye 10 gp Lantern, hooded 5 gp
Lock 10 gp Magnifying glass 100 gp
Manacles 2 gp Mess kit 2 sp
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MORE EQUIPMENT
Mirror, steel 5 gp Oil (flask) 1 gp
Perfume (vial) 5 gp Pickax 2 gp
Poison (vial) 100 gp Pole (3 metres) 1 gp
Pot, iron 2 gp Potion of healing 50 gp
Pouch 1 gp Rations (1 week) 5 gp
Rations, cured (1 week) 15 gp Rope, jute (15 metres) 1 gp
Rope, silk (15 metres) 10 gp Sandglass 25 gp
Shovel 2 gp Signal whistle 1 gp
Signet ring 5 gp Soap 1 gp
Spellbook 50 gp Spikes, iron (12) 1 gp
Spyglass 500 gp Tent, two-person 2 gp
Tinderbox 1 gp Torches (12) 1 gp
Vellum (one sheet) 1 gp Vial, empty 1 gp
Waterskin 1 gp Whetstone 1 gp
Why do you do this?
Roll, choose, or create your own
1 You have to be the first to find Rico. What do you have to give her?
2 You seek a rare material. What do you hope to turn it into?
3 You need to prove your theory. What piece of evidence is missing?
4 You are the strongest, the most worthy! (Who is the strongest?)
5 You soon will die. What will be your legacy?
6 You want to see the subterranean sights. What must you see before you die?
7 You have been tricked into this. How can you make even?
8 You want to be the most famous hero. What do you have to prove?
9 You want to prove Rico’s “findings” a hoax. Why won’t you let this rest?
10 You are engaged to Rico. Where did you propose?
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Converting saves
Ouroboros does not use saves typical to OSR games. Instead,
test the appropriate stat according to this guide:
• test SKILL versus man and monster
• test STAMINA versus the world
• test LUCK versus the gods
Time and turns
Play exists at natural speed, tactical speed, or montage speed.
At natural speed, individuals can attempt one major action
each ten minutes of game time.
At tactical speed, when it's especially important for the order
of who goes first, individuals can attempt one major action
each minute of game time. Combat takes place at tactical
speed.
At montage speed, individuals can attempt one major action
each hour of game time.This will often be described as a
montage, such as travelling or doing research.
Movement and distance
Space is considered in the same abstract way as time. Rather
than track exact distances, keep track of who is near who. On
their turn, individuals can move between groups or to empty
spaces. You need to be beside someone to attack them with a
sword. You can't be beside someone and shoot them.
Initiative
When it matters, the smallest side, and then side most at
home, goes before the others. Individuals act at the same
time as their teammates.
If it is necessary to break ties between players, whichever
player arrived first to the session goes first.
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Attacking and defending
• To attack a monster, players test their SKILL.
• To defend against a monster's attacks, players test their
SKILL.
• Consider individuals' locations when it comes to the range
of their attacks.
Damage and dying
When hit with an attack or another source of damage, in-
dividuals become hurt. When a hurt individual is damaged
again, they begin dying.
When no longer at tactical speed, dying players test their luck.
Failure means the character dies. Success means the player is
no longer dying and will remain hurt until they receive spe-
cialist care.
Armour
Individuals wearing armour ignore the damage from the first
X hits they take in combat:
• Light armour, such as leather and padded cloth, soaks 1
hit each fight.
• Moderate armour, such as chainmail, soaks 2 hits each
fight.
• Heavy armour, such as full plate, soaks 4 hits each fight
but imposes disadvantage on STAMINA tests.
• Shields soak 1 hit each fight but prevent use of ranged
weapons.
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Resting and healing
When in montage time, hurt players may attempt to rest up
by testing their STAMINA. Success means the player is no
longer hurt. Failure does not worsen the wound but has cost
valuable time.
Players who were dying cannot rest in this way without spe-
cialised care, such as first aid kits or healing magick.
If it would be important to determine if a monster has healed,
the Ref rolls a test against the monster's level.
Experience and levelling up
At the end of each session, surviving characters increase
their level by 1. When this happens, they may either increase
one stat of their choice by 1 point or gain a new specialisation
(related to their recent adventures).
When a new character is added to a group of a higher lev-
el, the Ref can decide to increase the character's level in line
with the group. When this happens, do not increase stats or
gain new specialisations.
Encumbrance
Players can carry eight distinct items. (Count one wallet rath-
er than twelve coins, &c.)
Their pace is slowed if they are:
• carrying treasure, or
• wearing heavy armour
This is likely to only be an issue if fleeing cave-ins or groups
of monsters.
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Random encounters
Every turn, except when playing at tactic speed, the Ref may
roll 2D10. If the dice match, this signals a random encounter.
It will be as many metres away as the total of the two dice.
Encounter reactions
When the players encounter an individual or a group, the Ref
may roll 1D100
• If the number is even, the encounter is friendly.
• If the number is odd, the encounter is hostile.
• If the digits match, the emotion is intensified.
• The higher the total, the more confident the encounter
feels in its position.
Morale
When every individual in a hostile group is hurt or the
leader has died, make a morale check. This behaves exactly
as a reaction roll, where the relative friendliness / hostility
modifies their current state. Do this no more than once each
encounter.
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SPELLS AND MAGICK
Spells are alive but we've yet no proof they're sentient.
Spellcasters jam spells in their brain when they want to
during montage time. Memorised spells cannot be dismissed;
they must be loosed by being cast.
Players with access to spellbooks can test their LUCK to jam a
spell in their brain. Failing this test means the player is hurt
and the spell has not been memorised. Players are welcome
to try again. Remember to add the level of the spell to the roll
if it is higher than the player's level.
Players can have as many spells as is their level memorised at
any one time.
CORE SPELLS
Merry's Potent Might
Level 1
An individual you can see gains the strength of a great beast
for ten minutes.
Tubular Insight
Level 2
The next four tests you make within the next minute are
made with advantage.
Esoterie of Senses
Level 3
Up to nine people who are in physical contact when the spell
is cast share all sensory experiences until they choose to dis-
engage from the gestalt.
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Ragnarocket
Level 4
Fire a psionic projectile that fuses an individual within six-
teen metres to the spot until they become hurt.
Pippin's Mattock of Provisions
Level 5
Conjures a mystical hammer that can be eaten during mon-
tage time. Up to five people may be healed of hurt.
Forged Charm
Level 6
Conjures a small trinket which, when eaten, treats the next
roll for a test as a six.
Twincasting
If a player has a spell memorised, they may test their LUCK to
create a copy of the spell at point of casting. The original spell
remains memorised and the copy's effects go off immediate-
ly. If this test fails, the spell is cast normally and the player
becomes hurt.
Spells from other systems
Most OSR spells can be ported directly in, when players find
them in spellbooks. If the spell does not have a level listed,
treat the level as 1. Monsters do not make rolls: if a spell
would call for a save, assume the monster fails the roll. For
cases that seem especially exploitable, come to a consensus
among players; if no consensus can be made, the spell is not
used.
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BESTIARY
SQUEET // LV1, moderate armour.
Venomous claws temporarily incapacitate.
Fluorescent, scaly birds, which scream at an irritatingly high
pitch. Idiotic and foolhardy, and attack in flocks.
BOW'S HEADSLUG // LV3 no armour.
An inch in length, camouflages well against stone, grass and
earth. Nocturnal; eats a path through the ear canal of anyone
fool enough to sleep nearby (LUCK saves).
SNUTWRECK // LV5, no armour.
Extremely fast: attacks made at disadvantage. Solitary, cat-
like creature – looks cute and fluffy, but do not approach.
Unzips its torso to engulf prey directly into its stomach.
ARCTORUS // LV7, light armour.
Changes its size in order to pursue prey. Bright blue spiders,
about the size of a hand – depends whose hand. Will swarm
anyone who disturbs them and burrow into the body via the
mouth, eyes and other orifices.
DURRELL'S OMISSION // LV8 heavy armour.
Armadillo-like, but without the charm. It targets the eyes
with deadly accuracy and a long, dripping tongue.
VANTA // LV10 no armour.
Immune to all poisons.
An enormous, grey-blue snake, with a cry that makes you re-
member being born. Swallows its prey whole; digestion last-
ing several weeks.
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JOHNSON SWIFT // LV1, moderate armour.
Small and rapid birds, with a bright pink tongue in place of a
head. They're driven to dissolve bright and shiny things, like
eyes.
Aerial mastery: melee attacks against them are made at dis-
advantage.
ARABACK // LV3, heavy armour
Stoic boars the size of a rhinoceros yet with even tougher
skin. They gather in loose herds and are most active at dusk.
SIGHTLESS SERPENT // LV6, heavy armour.
Unable to build their own tunnels, these subterranean lam-
preys are the length of three dead priests and hunt their prey
to exhaustion.
Rhythm sense: Sightless serpents know the location of any-
thing that moves within a kilometre that's in contact with a
surface.
MEDUSARUS // LV8, moderate armour.
The body of a giant black hound with 3 snake haired croco-
dilian heads. Protects passages to the underworld. Typically
accompanied by a few cerbrelings.
Cerbrify: Each day, each head can hideously transform a hu-
man it is biting into a cerbreling controlled by the medusarus
(LUCK saves).
CERBRELING // LV4, light armour.
Large black hound, the size of a mule, with three crocodilian
heads. Spawned by a medusarus.
Venoms: One head causes petrification upon a successful bite.
One head delivers a fatal toxin upon a succesful bite. One head
breathes fire. The first head to slay a human determines what
the cerbreling turns into upon maturity: petrification = me-
dusarus, poison = hydarus, flame = dracolus .
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HYDARUS // LV6, moderate armour.
Giant hound with green, leathery skin and three hissing croc-
odilian heads.
When one head is chopped off two grow in its place unless
salt is applied to the severed flesh.
DRACOLUS // Lv7, heavy armour.
Giant hound with thick red, leathery skin and three snake
heads.
Dragon breath: Each day, each head can breath a five metre
gout of fire that melts skin from bone and ignores armour.
ABANDOLITES // LV1, light armour.
Human children left exposed to die, harvested by the God of
Vacant Rot and given a final chance at life.
Pupate: Successfully killing and draining a human of its
blood, abandolites burrow into the husk of flesh and rapidly
grow to adolescence. An adolescent wakes without memory
but a base feral instinct, though remembers its early life in
nightmare, especially on the eve of its rebirth.
CHILDREN OF STYX // Lv3, heavy armour.
What happens if you dip an entire child into the River Styx?
They grow up invulnerable slaves to Hymn Braal. Humans
with glimmering skin, usually garbed in the weapons and ar-
mour of the underworld.
Immune to mundane attacks.
SLIME LORD // LV4, heavy armour.
A hulking slab of pulsating green flesh broken by a gaping
fissure for a mouth. The slime lord thrives in waste, mak-
ing homes in great sewers and noxious bogs, heralded by the
stench of rotting fish.
Swallow: Swallows its targets whole. If the swallowed re-
mains in the belly once the party enters montage time, they
die, dissolved in stomach acid.
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BLOOD FLY // LV3, no armour.
These spindly deep red flying insects, around the size of a hu-
man head, often attack in groups, seeking to suck the blood
of their prey. They have a long piecing proboscis and large
shimmering compound eyes.
Impregnation: After combat, anyone bitten by a blood fly tests
LUCK. On a failure they are infected with a larva, which erupts
in 2 days if untreated, causing harm. Removing it beforehand
causes harm unless the protagonist rolls a successful test of
SKILL.
ANT FOLK // LV2, medium armour.
Dwelling in large groups, foraging in packs, the ant folk are
humanoids with black chitinous skin, oval heads with large
opal eyes, sharp mandibles and never static antennae. Indi-
viduals live separate identities, but access a pheremonic hive
mind.
Hivemind: melee attacks against ant folk are made at disad-
vantage if another ant folk can see them.
ANT MIND // LV4, heavy armour.
The flying psychic heart of an ant folk hive, the ant mind is
far larger than their folk, preparing hosts for the gestation
of the next generation. If slain, remaining ant folk fall into a
confused state.
Ensnare: A sticky fluid is ejected from their abdomen that re-
strains (STAMINA saves).
LURKER // LV3, moderate armour.
A rough piece of stonework or the gnarled bark of a tree is in
fact a camouflaged strip of aggressive ooze that flings itself
at living things.
Defending against the first attack of a lurker is made with
LUCK.
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SKARRAN // LV2, light armour.
Rodents the size of wily children. Cautious and feeling safer
in numbers, they make traps to catch prey. Working in turns
they can gnaw through solid marble in an hour.
FUNGHUL // LV2, light armour.
Spore-ridden reanimated corpses, shambling forms bare-
ly recognizable as human beneath layers of fungal growth,
mushrooms sprouting from every orifice.
Reanimation: After battle, all protagonists test Luck. For each
fail, a hurt funghul reanimates.
CHROME GOLEM // LV5, heavy armour.
A hulking humanoid automaton, each surface of its body
gleaming like mirror.
Soul glare: If a subject catches a glimpse of themselves on the
golem’s body, they are bewitched for a round, incapacitated
(LUCK saves).
PANOPTORCHID // LV2, no armour.
This giant, ornate flower towers over the landscape on a
tough, woody stalk and has an unsettlingly eye-like pod in
the centre of its petals. Anyone within sight of the panopt-
orchid are paralyzed with fear until someone snaps them out
of it (LUCK saves). The panoptorchid periodically releases a
cloud of poisonous spores that deal damage if inhaled: these
are also analgesic and mildly hallucinogenic. Often deliber-
ately planted around wizard towers and fascist city-states.
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THALLASID // LV8, moderate armour.
These enormous, blind, scaly beasts with toothy maws are
found in huge lakes, wide rivers, isolated bays and other deep
bodies of water; their otherwise inexplicable presence in
these locales can only be the result of long-forgotten rituals
from before magic and science. They live for centuries and
eat only occasionally; subsisting primarily on the local pop-
ulations' mythical beliefs about the thallasid. They are noc-
turnal and rarely find the need to surface, contributing to the
rarity of sightings--but they will come up if belief in them
is waning, and are attracted by Important Events and people
who are likely to spread their tale, like bards and adventurers.
MULCH METEOR // LV1, no armour.
A vibrating mass of rotting leaves and soil which can be found
under dense forest canopies, buried in sinkholes, in caves
under ancient craters, and occasionally caged in a labora-
tory. It has an aura of despair, expressing as a keening vi-
brato that causes headaches and disadvantage. Blocking the
sound (with corks, sod, fingers, &c.) offers a LUCK test to end
the effect. The meteor inside the mulch longs to once again
streak through the sky, and moves slowly on the roiling mass
of forest loam surrounding its alien metallic core, searching
for clear access to the open air. Upon finding it, the meteor
will launch in a white-hot (and harmful) blast of energy.
GEFF // LV5 light Geff.
This ordinary looking man is actually Geff. If you aren't care-
ful, Geff will take Geff geff your mind. Geff could geff geff
anywhere Geff geff no warning. STAMINA test or Geff. Geff
geff geff geff geff GEFF GEFF GEFF GEFF GEFF GEFF GEFF
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BLUG // LV4, light armour.
Blugs are enormous eyeless gastropods which slowly creep
through their native habitats of moist forests and jungles,
secreting a sticky slime trail that traps unwary prey. Blugs
work in groups to slime an area and wait for prey to get stuck,
at which point they will approach and devour, slowly, with a
million tiny teeth. The slime ignites instantly on contact with
fire and burns blazing hot and blindingly bright.
SURICATIENS // LV2, light armour.
These small creatures with speckled fur have lanky bodies,
keen eyes, and sturdy claws. They live in complex networks
of burrows that they dig into chalky cliffsides and rocky,
arid regions, and have social hierarchies incomprehensible
to most humanoids. They hunt and eat scorpions, spiders,
beetles--even lizards and snakes--preferring the giant ver-
sions.
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