Basic paradigm: You have few limits to the number of abilities you can learn, but you can only access a limited number at a time.

You start a brand-new character with four trees that have three abilities in each plus one blank tree, but can learn new abilities in those trees or gain access to new trees to replace their blank ones through play. The maximum number of different ability trees a character has access to is equal to their level, and every time an adventurer levels up they gain a new blank tree.

While you can learn any amount of abilities, you can only equip a number of abilities at a time equal to your level. Pick abilities at the beginning of each new session. You can change your chosen loadout any time by spending a point of Supply, or for free when you're in a friendly establishment that has an armory.

Supply is an important concept in Annulus. Why do people use crossbows after the apocalypse when guns are available instead? Among other reasons, because ammunition is much easier to get and often reuseable. An adventurer's sum total of expendable resources- ammunition, food, medicine, potions, magic scrolls, grenades, cash money, etc- is all rolled together into one single resource called Supply. Every player starts each session with 10 Supply, represented by blue chips.

Enemies and NPCs have Supply too, but only 3 instead of 10. Players cannot loot Supply off defeated foes under normal circumstances.

• When supply is used up, you give one of your blue chips to the GM. If you have no supply chips left, you cannot use any abilities that could potentially consume them.
• Players can give a supply chip to an adjacent creature with an action. Share all you like.
• Supply is replenished at the beginning of each new session. Sometimes you can find small caches of supply during an adventure as a reward (see Rewards for more info on Supply caches).
• You can feed yourself for a day outside of civilization by spending one Supply.
• You can change your entire loadout of equipped abilities for different ones by spending a point of Supply. This can be done instantaneously at any time.
• Some attacks will consume supply if the Trigger Die shows a low enough number. Different types of weapon consume supply at different rates- bows very rarely consume any Supply, but grenades and flamethrowers eat through it rapidly.
• Many other abilities and effects can randomly consume supply as well via use of a trigger die.
• You can use Supply to bargain with other creatures in the game world or as payment for goods/services.
• You can pay a lump sum of Supply to learn a new ability, but only when you have an appropriate keystone.
• You can spend 5 Supply to buy a point of Capital. Capital can be used to establish or improve various establishments in the game world.

A “condition” is any negative, ongoing effect. There's a list of them on the Miseries page. At the end of each turn in which you've suffered from a condition, there's a chance that you throw it off and don't have that condition anymore. Roll a trigger die- if the result is 9+, that condition is removed. You only get a chance to throw off conditions after your turn has ended (you've taken both actions). If you're suffering from multiple conditions at once, roll once to get rid of each of them. Announce which condition you're rolling for before you toss the die- no fair rolling first and picking which you can or can't live with.

If you really need to get rid of a condition, you can also chose to dedicate your entire turn to getting rid of it. By spending both actions doing nothing except focusing on recovery, you may make a bonus recovery attempt against every condition you're currently suffering from. This is in addition to the normal free attempts you get at the end of each turn.

Different games cater to different tastes, and one of the things that affects a game the most is the possibility (or not) of the random, cruel and permanent death of its heroes. Some players love the heightened tension that this brings, while others hate the potentially choppy and depressing narratives that such games create. In Annulus, your group has a choice from between two options:

Adventurers are just like anything else in the game world- if they run out of Vitality, they're dead and that's that. A player can create a new adventurer in order to rejoin the game, but the old one is gone. This keeps the tension high and the survivors wary.

Combat in Annulus is fast and deadly. If you play by these rules, be careful never to allow yourself to be surrounded and always keep an escape route in mind. Try to avoid combat if possible, or at least tip the odds as far in your favor as you can before jumping into the fray. Numbers matter more than level: a large horde of low-level enemies can be just as if not more deadly than a few high-level ones, so if you find yourself outnumbered it might be best to run away before you get cut down where you stand.

Adventurers are important to the plot, allowing them to cheat death on a regular basis. An adventurer that runs out of Vitality doesn't die but merely falls unconscious. They can be slapped awake with ten rounds of constant work, or will wake up on their own a few hours later. After waking up, an adventurer that was “killed” regains one Vitality and gains an injury of the GM's choice.

Even in a game using the Heroic character death rules, they are completely optional. When an adventurer dies, their player can choose to have them truly die for real if desired (such as in the case of a dramatic and heroic sacrifice).

Heroic rules protect adventurers from death, not from failure. If the party is wiped out in a climactic battle while trying to prevent a Bad Thing (a demon lord from being summoned, a corrupt CEO from buying up all the shares in their company, an ice cream vendor from selling all the lemon pops, or whatever) then it can be safely assumed that the Bad Thing happens. When the party wakes up, they will have to live with the consequences of their failure.

The GM periodically performs a random encounter check by rolling a trigger die (or better yet, getting a player to do it). On a 1-4, an encounter occurs. When the die result is 4, the players notice the random encounter but are as of yet unnoticed themselves. On a result of 1, the reverse is true (and the players will likely be ambushed, depending on the temperament of the encountered creatures). On a 2 or 3, the players and the encounter notice each other at approximately the same time.

How often is “periodically”? There is no set rule. The GM makes a check when time passes or the action has slowed. The following are all good times to make a random encounter check:

• When entering a new room in a high-danger area (such as a dungeon).
• When spending a lot of time in one dungeon room (such as when performing an operation).
• When somebody uses a loud ability (such as a firearm).
• Once or twice per day when traveling overland.

The GM will have a list of random encounters to draw from specific to the area you are in.

Weight is not tracked for equipment such as weapons, Supply, and so forth- it's assumed that every adventurer can carry their basic tools and necessities by default without any further worry. Weight is only tracked when a creature starts carrying other creatures around.

Every creature (and a number of non-creature devices such as artillery and boats) has a size category- a deliberately non-exact measure of its approximate mass/volume. A creature's size category determines the number of spaces it occupies on the battlefield, how hard it is to carry (measured in similarly-abstracted units called Bulk) and how much bulk it can haul before it starts to suffer negative effects from it.

• Space is a simple measure of how much room a creature needs to move around on the battlefield. The human norm is 1 space. Larger creatures occupy a space and all other spaces within a given distance from it- size category 6 creatures, for instance, have a rating of “+1” and thus occupy one space and all other spaces within 1 meter of it. Large creatures determine their facing visual arc from their center space and the range of their abilities from whichever space they occupy that is closest to their target. Smaller creatures occupy fractions of a space, which means that multiples can fit into a single space (and in the case of very small size categories, this can be a lot.) Don't go crazy counting the total numbers of rats or whatever occupying each space unless it is really important to know at the time.
• Bulk is an inexact representation of both mass and volume to represent how difficult the creature is to carry. Humans and other size category 5 creatures have a bulk of 1. Bulk increases rapidly with size, and decreases similarly rapidly.
• Encumbrance is the uppermost amount of bulk that a creature can carry as a light load. If a creature carries any more Bulk than the listed limit, they are encumbered (they take an impairment to all movement and suffer +2 damage from all incoming attacks). A creature can haul Bulk up to their own body's worth as a heavy load with encumbrance, but no more. For instance, a human can carry up to 1/5 of a Bulk without it slowing them down at all, or up to 1 Bulk with an impairment.

Any time a player has a significantly positive interaction with any NPC, they can optionally roll to befriend that NPC. This requires a result of 9+ on a trigger die. If successful, the NPC and the player's adventurer become friends. NPCs that are already friends can have their relationship with the adventurer increased to become a bond by rolling an 11+, which represents something more akin to a family member or lover. Players can amass as many friendships and bonds as they care to, but cannot roll to establish or increase any given relationship more than once per session.

NPCs with good relations will happily aid their friends, or take significant risks on their behalf if they are bonded. This system is mostly a neutral support to role-playing but has a few mechanical effects as well.

Certain effects might give an “impairment” to movement speed. Normally, every one-meter space costs 1 move speed to enter and so move speed is equal to how far you can physically go per move action. Impairments significantly slow down movement by increasing the move speed cost to enter a space, as such:

Multiple impairments from different sources stack with each other. If you have enough impairments that the cost of entering a space is higher than your movement speed, you can spend multiple actions storing up movement speed until you have enough.

When you're in zero-gravity, you can move in one of two different ways: crawling along a solid surface (move with two impairments) or push off a solid surface. Pushing off costs an action and allows you to move a distance up to your speed in a chosen direction. Roll a trigger die when pushing off; if the result is 1-2 you accidentally push off a hex's deviation to the left of your intended path and if 3-4 you are a hex's deviation off to the right instead.

Momentum is not lost in space. After pushing off, you continue traveling the same direction at the same speed as before at the beginning of each new round after regaining Flow but before taking actions. This additional movement costs no actions and happens whether you want it to or not. You cannot stop or change directions except by running into another solid object.

If you gain more velocity while moving in space, it is added to the velocity you already had. For example, if you were traveling 1 meter/round straight forward and then something happened to make you move 1 meter/round to the right, your new velocity moves you one meter forward AND one meter to the right every round. Adding velocity in the exact opposite direction that you are already traveling simply cancels out- 1 meter/round forward and 1 meter/round backwards means you don't move at all.

While nothing has any weight in zero-gravity, more massive objects are still more difficult to move and manipulate. If you could carry an object in normal gravity without it giving you an impairment, you can simply throw it around in zero gravity as an action (imparting a velocity of up to 5 meters per round to it). Objects large enough to give you an impairment to movement speed can also be shoved where you want them to go, but doing so confers a maximum velocity of 1 meter per round.

Every time you throw an object or use an attack ability, you are propelled 1 meter per round in the opposite direction. When using attacks, if the trigger die is 1-4 you also spin out of control and gain a failure chance of 6 with all further attacks until you get the chance to stabilize yourself against something solid. Stabilizing yourself takes an action. Beam attacks are an exception to this; using one does not propel you backwards and has no chance to cause you to spin out of control.

Vacuum is an airless environment, imposing an unrecoverable Choking condition to those who enter it for as long as they stay just like other airless environments. Vacuum's harsh blend of pressure, chill and radiation also has the effect of removing 1 point of Vitality per round from those who enter it without any sort of protection. This Vitality is removed at the end of each turn of exposure.

Living long-term in zero gravity has bad effects on creatures meant for an environment with gravity in it- bones become fragile, muscle mass decreases, and various other problems can arise such as balance disorders. After every day of life in continuous zero gravity, a creature must roll a trigger die. If the result is a 1, their maximum Vitality is immediately reduced by 1 point. This can reduce a creature's maximum Vitality to 1 but not below 1. To regain lost maximum Vitality, the subject must spend a full week in a normal-gravity environment for every such point lost.

Regular movement is measured in meters per action. Journeying is movement measured in regions (10 km hexes) per day and is used when traveling from point A to point B in the game world. A creature's journey rate is equal to their regular movement rate- for instance, a creature with the normal default move speed of 5 meters per action has a journey speed of 5 regions per day.

Journeying through wilderness gives an impairment to journey speed. Particularly rugged wilderness (such as thick jungles) confer two impairments instead. Journeying has no impairments through civilized regions or those with roads/canals/etc. Wilderness areas with little or no barriers to movement (such as ships on the open ocean) do not confer an impairment to journey speed of those passing through them.

Travelers in a hurry can choose to perform a forced march once per day. A forced march allows a second move during the same day. This second move has an impairment (stacking with any impairments from terrain). Performing a forced march inflicts 1 point of Vitality damage to all the marchers and inflicts a Fatigue condition on them that cannot be recovered from normally. Taking a day to do nothing but rest removes the Fatigue condition from forced marches. Multiple forced marches on successive days will inflict stacking Vitality damage but not increase the effect of the Fatigue condition. Travelers cannot choose to force march more than once per day.

Some ability trees (Boat, Wheels, Aircraft, Spacecraft?) give you a vehicle. Vehicles all have certain characteristics and rules in common that I'm going to put here instead of copy-pasting into every tree's description in order to cut down on scrolling a bit.

Vehicle Basics: Vehicles are kind of like creatures but also kind of not. Your vehicle is considered to be the same level you are for purposes of how much Flow/Endurance/Vitality it has, and uses the combat abilities of whoever is steering it for defensive purposes. If nobody is steering it, all combat abilities are 0. Vehicles don't have abilities or Supply of their own. All vehicles are immune to the Choking, Poisoned, Bleeding, Dazed, Fear, Confused, and Charmed conditions. Attacks that are capable of dealing the Poisoned condition have a failure chance of 8 against vehicles.

Vehicle Size: Your vehicle can be any size you want, within reason and the constraints of technology that exist in your campaign world. Note that your vehicle will need to be at least the same size as you are in order to carry you at all, and bigger if you want it to carry your friends and/or junk. Your vehicle's size determines how much space it occupies, how much it can carry, and failure chances on attacks made against it just like a creature (see Size and Weight in Game Concepts for more information).

Vehicle Movement: When you're in your vehicle, you can spend an action to move it (along with everything it's carrying, including you.) Vehicles are fast and can go 10 meters per movement action instead of the normal 5 meters. Moving a vehicle is not like moving yourself; any abilities you may have equipped that enhance your own movement (such as Mobility or Slippery) do not apply to your vehicle. Vehicles cannot sprint. If preferred, you can designate somebody else on the vehicle to act as its pilot instead of yourself, in which case they spend their actions to move it and you can do whatever you want with yours.

Vehicle Crew: Vehicles need to be crewed. An uncrewed vehicle cannot move and all combat scores are 0 for defensive purposes. The vehicle's size determines its crew requirements- larger vehicles require larger crews. Creatures larger than size 5 can act as multiple crew members equal to their Bulk (so a size 6 creature acts as 5 crew members, a size 7 as 20 members, and so on). You can act as one crew member, and party members, minions or hirelings can fill in the gaps. Every time the vehicle's pilot spends an action to move it, every member of the crew must spend an action as well. Passengers that are not acting as crew members can take whatever actions they wish as the vehicle moves. Note that crews require rations to undertake long journeys.

Limited Turns: While faster than creatures, vehicles are frequently also less agile and can take a bit of time to bring around to a new heading. Vehicles are limited to one direction change of no more than 1 hex's diversion (60 degrees) from their previous course per action spent moving.

Vehicle Dangers: When an attack targeted at your vehicle has a trigger die result of 7+, the attack also strikes any single pilot or passenger riding in the vehicle of your choice. If it was an Area attack, it strikes three creatures of your choice (but no more than once each).

Vehicle Collisions: You can smash a vehicle into things. This deals damage to the vehicle, all its passengers/crew, and whatever it smashed into (plus all of the obstacle's passengers/crew if it's another vehicle) equal to the current Escalation, and immediately applies the Grabbed condition to both the vehicle and whatever it smashed into in relation to each other. Damage from vehicle collisions is typeless and cannot be reduced by combat defenses.

Vehicle Destruction: If a vehicle is destroyed or sunk, every creature riding on it must immediately roll a trigger die. If the result is 7+, they get clear of the wreck without any further trouble. If not, then they are trapped by it and immediately gain a Grabbed condition from the vehicle.

Too Big To Carry: If you go somewhere your vehicle can't, you can't bring it with you. It stays wherever you left it until you come back for it. You don't have to keep your vehicle-granting abilities equipped when you're not using it.

Insurance: If your vehicle gets wrecked, lost, stolen, blown to smithereens or you just plain don't want to go back for it you can get a new one in exchange for five Supply anywhere that similar vehicles can be found.

Every creature has a limited number of inventory slots that can be used to carry useful things. Adventurers have six; NPCs generally have two or none.

Inventory slots are not used to carry things represented by your abilities; abilities are a combination of equipment, training, and biology that may or may not have weight at all. You're assumed to be carrying everything you need to use your abilities at all times without it taking up any inventory slots.

Here's a few common items that might occupy inventory:

• Stock. Stock is used to carry Supply. Each Stock in your inventory can hold up to 5 Supply in it, and Stock gets removed when the last Supply in it is spent. Adventurers get one new Stock with a full 5 Supply in it for free at the beginning of each new session to represent their side hustles, wages, or resupply runs between adventures. You don't need to worry about Stock when spending Supply in an establishment or base, but you need it in order to take any Supply out into the field with you.
• Keystone. Keystones are items that allow you to learn a new ability from a particular tree. Every keystone is tied to a single tree. You can use keystones any time you have a few minutes, but using keystones also carries a Supply cost that increases with more abilities known in the keystone's tree. Keystones can be sold for 1 Supply in any establishment.
• Treasure. Treasures are things that are both valuable and portable. Their only purpose is to be sold in an establishment for a variable amount of Supply. Roll a trigger die when selling treasures: 1-3 means 1 Supply, 4-6 means 2, 7-9 means 3, and 10+ means 4. You can also just roll a four-sided die if you have one handy, the odds are the same.
• Luxuries. Luxuries are more pleasant or interesting than they are inherently valuable, such as fine food, body paints, or incense. A luxury counts as 3 Supply for purposes of carousing in an establishment to gain extra XP, or can be sold for 1 Supply instead.
• Capital. Capital is raw materials, expertise or vouchers that can be used in any establishment to further develop it. Different upgrade tiers to an establishment cost different amounts of Capital, but spent Capital remains stored between sessions. Capital can also be sold off for 1 Supply if preferred.
• Rations. Rations are big bundles of food. If you have a ration in your inventory, you can feed yourself for a day outside of civilization. Roll a trigger die when you do; if the result is a 1-4 the Rations get erased from your inventory after using it. You can feed others with your Rations as well, but you have to roll for depletion once per such creature fed. You can turn a dead creature into a Rations item if it's the kind of creature that's commonly edible, but if it's something weird or highly magical it gets turned into a Mystery Meat item instead. Mystery Meat acts as a Rations item but causes its eater to gain a random mutation if they roll a 1 on the depletion check.
• Utility. Inventory slots can also be used to carry any useful item (such as light sources or ropes), trinket or macguffin you happen to pick up that isn't directly related to any of your abilities.
• Other. Some abilities provide unusual things that can be put into inventory slots- for example, Debtor from the Merchant tree allows you to fill inventory slots with “Debt”.

Everything in your inventory can be carried over from session to session indefinitely. Everything that isn't in your inventory is assumed to be lost, consumed or wasted between sessions.

Defeated enemies or random corpses can be looted by taking time to pat them down, with potential rewards determined by a trigger die result. A 1-6 yields nothing, a 7-10 yields a keystone corresponding to one of the ability trees the creature had equipped, and a 11-12 yields one treasure.

You can roll one loot check for every 5 levels possessed by the creature you're looting. This means that it isn't possible to loot anything from a creature of level 1-4, but you can roll to loot a level 10 creature twice, a level 15 creature 3 times, and so on.

Every game needs a random chart full of gonzo-ass mutations. Mutations might arise from radiation, eating mystery meat, magical mishaps, or exposure to cosmic abominations. Chart entries are meant as general guidance for the GM, who can go into as much detail as they please in describing the new mutation's exact appearance and nature.

Roll a trigger die when you mutate. You might or might not need to roll another one after for more information.

Radiation is a more subtle environmental hazard than something like lava. It is invisible and intangible; being in an area of radiation can normally be inferred only from context (such as sparse, dying or mutated vegetation).

Every time you are exposed to a dose of radiation it inflicts the Fatigue condition to you. If the radiation exposure came from an ongoing source in the environment, you cannot recover from the Fatigue condition until you leave the source behind. Every time you're exposed also requires a trigger die roll to determine the secondary effects of the radiation:

• 1-4. You lose one Vitality and become irradiated (see below).
• 5-10. You lose one Vitality as your body degrades.
• 11-12. You gain a new random mutation over the course of the next few days.

Irradiated: Being irradiated is sort of like a condition that cannot be thrown off normally. It lasts for one day after you leave the source of radiation behind. You can get multiple stacks of Irradiated, extending its duration by +1 day each time. Days spent irradiated give an extra dose of exposure to both you and everyone that spends a significant amount of time in your company. This secondary exposure cannot itself cause or extend Irradiated- treat all results of 1-4 for yourself or those in your company as results of 5-10 instead. Being irradiated prevents you from recovering from the Fatigue condition inflicted by radiation, since you've become your own source.

Most areas of high ambient radiation give one dose of exposure per day spent in them, but higher exposure rates (such as once per every few minutes or even once per round) are also possible. Some abilities in the Curie tree also deal out doses of radiation.