---
title: 'HOSR Core Rules: Adventuring'
description:
date_pub: 2023-04-26T23:02:00-04:00
section: rules
content_type: feature
short_code: uha
---

[[toc]]

### Ability Checks

Simple tasks are assumed to succeed. If the task is dangerous or complicated, roll the dice for an Ability Check.

For most checks, roll a 20-sided die (d20) and add the ability's modifier.

-   The Referee may also add a situational modifier to the roll, typically between -4 and +4.

Then, check the results of the roll:

-   A natural 20 means a critical success: the check succeeds, and often includes a bonus for the roller.
-   An 11 or higher is a success.
-   A 6-10 represents a partial success: the check succeeds, but with a potential complication or challenge for the roller.
-   A 5 or less is a failure.
-   A natural 1 means a critical failure: the check fails, and often includes an extra complication or challenge for the roller.

### Exploration Procedure

The general steps to take when exploring (dungeon, wilderness, etc.)

1. **Setup**: Referee describes the situation
2. **Marching Order**: Party determines general exploration process, including direction of travel and speed.
3. **Complication Check**: Referee rolls the complication die to see what effect it has.
4. **Actions / Responses / Complications**: Party declares actions, referee describes the results (and any complications).
5. **End Turn / Watch**: When the party has gone far enough or combat has completed, the (dungeon) turn or (wilderness) watch ends.

    - Dungeon: 180'
    - Wilderness: 6 miles

6. **Repeat**: Return to step 2 and repeat until the adventuring ends.

#### Complication Check

Roll 1d6, ignoring results of 4+ for the first 4 turns in a session (or since they last occurred).

1. **Encounter**: Wandering creature, social encounter, or some other random interaction.
2. **Signs / Portents**: Indications of possible encounter nearby - could be a clue, monster tracks, etc.
3. **Locality**: Some environmental or external event that affects the PCs - water rises, the assassin gets closer to the target, doors lock behind the party, etc.
4. **Fatigue**: Party must rest for 10 minutes (1 turn) or gain a level of [exhaustion](#exhaustion).
   5+ **No Complications**

### Conditions

#### Darkness

-   If unable to see, treat as [blinded](#blinded).
-   Candles light 10' radius.
-   Torches / lanterns light 30' radius.

#### Infravision

-   Can see heat tones, even in the dark.
-   Usually works to 60'.

#### Listening at Doors

Spend a minute listening at a door to have a base 1-in-6 chance of hearing a noise.

-   Referee makes this roll.

#### Opening Doors

-   Locked Doors can be picked or broken.
    -   Picking a lock takes 1d6 minutes.
-   Stuck Doors can be unstuck or broken.
-   Doors always break on a 1. Failure can affect stealth / surprise.

<div class="dividedTableWrapper">

|  STR  | Unstick | Break  |
| :---: | :-----: | :----: |
|  3-8  |   ---   | 1-in-6 |
| 9-12  | 2-in-6  | 1-in-6 |
| 13-15 | 3-in-6  | 2-in-6 |
| 16-17 | 4-in-6  | 3-in-6 |
|  18+  | 5-in-6  | 4-in-6 |

[Forcing Door Chances]

</div>

#### Other Hazards

-   Fall damage is 1d6 / 10'.

#### Swimming

-   Creatures are assumed to be able to swim at 1/2 their normal movement speed.
    -   Unless the creature is just floating, a STR or CON check is required every turn (10 minutes).
        -   For creatures carrying heavy loads or wearing metal armor, this check is required very combat round (10 seconds).
        -   Failing this check results in a loss of 1 HP, and the check must be immediately attempted again.
        -   The third failure indicates the creature begins [drowning](#drowning).

#### Drowning

-   Each combat round, a drowning creature must **Save vs Death** or take 1d8 drowning damage.
-   When a drowning creature is rescued, it gains 1 level of exhaustion.
-   Once the exhaustion is cleared, the creature gains back any HP lost to drowning.

#### Urban Navigation

To navigate to a location in a busting city, make a Reaction Roll (2d6) + CHA mod + INT mod.

-   Modify roll in friendly, dangerous, or especially alien areas.
-   Navigation time includes time spent reading maps and getting directions, as well as any eating or rest stops needed along the way.
-   Roll random encounter checks each hour

<div class="dividedTableWrapper">

| Roll |  Result   |       Time Spent       |
| :--: | :-------: | :--------------------: |
|  2   |  Failure  |  Waste day searching   |
| 3-5  | Wandering | Arrive after 2d4 hours |
| 6-8  |  Success  | Arrive after 1d6 hours |
| 9-11 | Fortunate | Arrive after 1d4 hours |
| 12+  |  Direct   |  Arrive after 1 hour   |

[Urban Exploration Results]

</div>

#### Wilderness Exploration

-   Distances and non-magical ranges are tripled (yards rather than feet).
    -   Areas of breath weapons and spell effects are still measured in feet.

**Flight**

-   Unless stated otherwise, flight distance is double that of overland travel.
    -   Flight speed is not affected by terrain.
-   Winged beasts may be used as **mounts**, carrying riders or cargo based on the mount's HD:
    -   3 HD: May carry a creature 1/2 the size of a humanoid.
    -   6 HD: May carry a creature the size of a humanoid.
    -   12 HD: May carry a large creature (ex: horse)
    -   24 HD: May carry a huge animal (ex: elephant)

<!--

**Foraging**

-   May be performed while traveling at normal pace.
-   Party has 1-in-6 chance of foraging enough for 1d6 characters

**Hunting**

-   Takes a complete day (no travel or resting possible).
-   Party has 1-in-6 chance of encountering game.
    -   This is in addition to normal random encounter chances.

**Light**

A full moon (or fog, heavy rain, etc., during daytime) with a
clear sky will create an area of dim light. Otherwise, night
and very thick fog will create darkness. See the Dungeon
Adventures section for the effects of darkness.

**Losing Direction**

-   At the start of each day, referee should roll to determine if group loses direction.
-   Chance of losing direction depends on terrain being traversed:
    -   Grasslands, plains, clear: 1-in-6
    -   Hills, mountains, woods, barren areas: 2-in-6
    -   Swamp, jungle, desert: 3-in-6

-->

**Overland Travel**

-   The distance in miles that a character can travel overland in a day (16 hours) under normal conditions (and clear terrain) can be determined by multiplying their base movement rate by .6 (or 3/5).

    -   10' / round => 6 miles / day
    -   20' / round => 12 miles / day
    -   30' / round => 18 miles / day
    -   40' / round = 24 miles / day

-   Some terrain affects overland speed while traveling through it:

    -   Maintain roads: Increase speed by 50%.
    -   Hilly, wooded, or desert terrain: Decrease speed by 33%.
    -   Swampy, mountainous, or jungle terrain: Decrease speed by 50%.

-   Characters engaged in a forced march can increase their travel speed by 50%, but must rest for a full day or suffer 2 levels of [exhaustion](#exhaustion).

-   Characters can travel for up to 6 days before they must rest for at least 1 full day.
    -   For each day beyond the 6th that they travel without resting, they gain a level of [exhaustion](#exhaustion).

**Sight**

Characters can usually see 3 miles around (in clear terrain).

-   Range of sight may vary based on terrain (ex: less in wooded area, more on an overlook).

### Encounter Procedure

1. **Check Stealth**: Referee rolls for stealth, if applicable.

    - Each side that's being relatively stealthy (quiet, douses torches, etc.) has a base 2-in-6 chance of not being spotted.
    - Parties carrying an active light source typically can not have stealth.
    - If only one side has stealth, they may usually make a free attack (or can pass unnoticed).
    - If all sides have stealth, they miss each other.

2. **Determine Distance**: Referee determines how far away the characters are from the encounter.

    - Often determined by the nature of the encounter itself, but may be determined randomly:
        - Dungeon: 2d6 x 10'
        - Wilderness: 4d6 x 10 yards (or 1d4 x 10 yards if either side is surprised).

3. **Roll Initiative**: Each side rolls 1d20, highest roll moves first.
4. **Choose Actions**: Each side decides how they will respond in initiative order, and the encounter proceeds.
    - Players decide how their characters will act.
    - Creature actions are often determined by the nature of the encounter itself, but may be determined randomly.
        - If creature / NPC reaction isn't obvious, roll 2d6 (+ CHA modifier, if someone tries to communicate).

<div class="dividedTableWrapper">

| 2d6 |   Result    |
| :-: | :---------: |
| 2-  |   Attack!   |
|  3  |   Hateful   |
|  4  |    Leery    |
|  5  |    Rude     |
|  6  |    Aloof    |
|  7  |  Uncertain  |
|  8  |  Confused   |
|  9  | Indifferent |
| 10  |   Cordial   |
| 11  |   Amiable   |
| 12+ |  Friendly!  |

[Reaction Table]

</div>

<div class="dividedTableWrapper">

|  CHA  | Mod |
| :---: | :-: |
|   3   | -3  |
|  4-5  | -2  |
|  6-8  | -1  |
| 9-12  | +0  |
| 13-15 | +1  |
| 16-17 | +2  |
|  18+  | +3  |

[Charisma Modifier]

</div>

5. **End Turn**: Once the encounter has played out, the turn ends.

-   Each encounter is assumed to take at least one full turn to complete.
    -   This includes time to regroup, bind wounds, clean weapons, etc.

#### Typical Actions

While any action is possible, the following actions are the most common:

-   **Combat**: If a side attacks, casts a spell, or makes a tactical movement, [combat](./combat.html) begins.
-   **Evasion**: If a side decides to flee, another side may decide to pursue.
-   **Talk**: One side may attempt to communicate with the other(s).

#### Evasion

Any side that wishes to avoid an encounter may attempt to flee.

-   Only possible before combat begins.
-   Each opposing side declares whether or not they want to pursue.
    -   Players decide freely if they wish to pursue fleeing creatures.
    -   Referee decides whether creatures pursue fleeing PCs (based on circumstances or roll).
-   If all opposing sides decide not to pursue, the evasion attempt automatically succeeds and the encounter is avoided.
-   If an opposing side decides to pursue, the chance of evading depends on the surrounding environment.

### Advancement

As the adventures continue, treasure is acquired and creatures are vanquished, all adding to the PCs XP total.

-   Each standard coin worth of treasure gained is worth 1 XP, and each creature has an XP value awarded for beating them (one way or another).
-   The total XP are then divided amongst the PCs and any hirelings they have (at 1/2 share per hireling).
    -   Players running multiple characters gets a full share for their first PC and a half-share for the second, although they choose how to distribute the points.
-   Referees may increase the derived value arbitrarily.
-   Once a PC acquires enough XP, they go up to the next level in their class.

<!--
Thinking about making this either session based, adventure based, or something along those lines.
-   How can I note the rules while keeping them _super vague_?

You gain 1 Advancement Point for each major challenge or obstacle you overcome.
-   In practice, this amounts to somewhere between 1 point per session and 1 point per adventure.
-   When you have as many Advancement Points as your current level, you gain another level.
-   When you gain a level, your advancement point count resets.
-->

#### Upon Gaining a Level

When a PC increases their level, the following actions may be performed:

-   Roll a hit die (based on the PC's class), and add it to their maximum hit points.
    -   1s and 2s may be re-rolled.
    -   Alternatively, roll the next die step down and add 2.
-   Their player may pick one of the PC's abilities, and roll 3d6.
    -   If the resulting roll is higher than the ability score, increase the score by 1.
-   Check the PC's [class](/classes/index.html) and [race](/races/index.html) to see if any new abilities are gained.

### Conditions

#### Blinded

-   A blinded creature:
    -   can’t see,
    -   automatically fails any ability check that requires sight, and
    -   only hits on a natural 20 (as a critical hit).
-   +4 to attacks against a blinded creature.

### Deafened

-   A deafened creature:
    -   can’t hear, and
    -   automatically fails any ability check that requires hearing.
-   +2 to attacks against a deafened creature.

#### Exhausted

-   An exhausted creature:
    -   gets -1 to _all_ rolls, and
    -   has their AC reduced by 1 for each level of exhaustion they have.
-   Each level of exhaustion can be cleared by resting for 4 hours (1 watch).
-   Gain 2 levels of exhaustion per day without a long rest.

<!--

#### Frightened

Most (unintelligent) frightened creatures will flee from the source of their fear.

    A frightened creature has disadvantage on ability checks and attack rolls while the source of its fear is within sight.
    The creature can’t willingly move closer to the source of its fear.
-->

#### Invisible

-   An invisible creature:
    -   can't be seen without magic or a special sense,
    -   can only be tracked by any noise it makes or tracks it leaves, and
    -   gets advantage on attacks.
-   Attacks against an invisible creature have disadvantage.

#### Paralyzed

-   A paralyzed creature:
    -   is unable to speak, move, attack, or take any actions; and
    -   automatically fails any ability check that requires movement or speech.
-   Attack rolls against a paralyzed creature have advantage.
    -   If the attacker is within 5 feet, any attack that hits is a [critical hit](./combat.html#critical-hits).
    -   Optionally, the referee may rule that a paralyzed creature can be instantly killed (ex: slitting its throat).

#### Petrified

-   A petrified creature:
    -   is transformed, along with any nonmagical object it is wearing or carrying, into a solid inanimate substance (usually stone);
    -   is unable to speak, move, attack, or take any actions;
    -   automatically fails any ability check that requires movement or speech;
    -   ceases to age;
    -   weighs 10x their normal weight;
    -   only takes 1/2 damage from everything except explosives and pick-type weapons; and
    -   is immune to poison and disease (although a poison or disease already in its system is suspended, not neutralized).
-   Attack rolls against a petrified creature have advantage.
    -   When attacked and the attacker fumbles, their weapon breaks.

#### Poisoned

A poisoned creature has disadvantage on attack rolls and ability checks.

#### Prone

-   A prone creature:
    -   moves at half normal speed,
    -   can stand up for half its normal speed (ending the condition),
    -   has disadvantage on attack rolls.
-   When attacking a prone creature:
    -   melee attacks have advantage, and
    -   ranged attacks have disadvantage.

#### Restrained

-   A restrained creature:
    -   can't move, and
    -   has disadvantage on attack rolls and ability checks that require moving.
-   Attack rolls against a restrained creature have advantage.

<!--
```
Stunned

    A stunned creature is incapacitated (see the condition), can’t move, and can speak only falteringly.
    The creature automatically fails Strength and Dexterity saving throws.
    Attack rolls against the creature have advantage.
```
-->

#### Unconscious

-   An unconscious creature
    -   is unable to speak, move, attack, or take any actions;
    -   automatically fails any ability check that requires movement or speech; and
    -   is unaware of their surroundings.
-   When a creature is rendered unconscious, they drop whatever they are holding and fall prone.
-   Attack rolls against an unconscious creature have advantage.
    -   If the attacker is within 5 feet, any attack that hits is a [critical hit](./combat.html#critical-hits).
    -   Optionally, the referee may rule that a paralyzed creature can be instantly killed (ex: slitting its throat).

### Encumbrance

Characters can carry a number of "Important Items", based on their Strength (STR).

-   Items can be carried **At Ready** or **Packed**.
    -   "At Ready" items may be grabbed and used without delay.
    -   Packing or unpacking items takes 1 turn.
-   Characters can carry a number of at-ready items up to their Strength (STR), to a minimum of 7.
    -   Additionally, characters may carry a number of packed items up to their Strength (STR), to a minimum of 7.
-   Leather armor (with or without studs) counts as 1 item, chain mail and half plate each count as 2 items, and full plate counts as 3 items.
-   2-handed weapons count as 2 items.
-   100 coins or gems count as 1 item.
-   Carrying more ready or packed items than allowed can be done, but movement is halved (or worse).
    -   Carrying more than twice the allowed number of ready or packed items reduces movement to 0.

### Health, Damage and Dying

The state of a character's health is determined by their number of hit points (HP).

-   Starting HP is usually determined by class and level.
    -   The type of Hit Dice to throw is determined by class
    -   The number of Hit Dice to throw is determined by level.
    -   Re-roll any 1s or 2s.
    -   Modify the rolled value of each die by CON as below:

<div class="dividedTableWrapper">

|  CON  | Mod |
| :---: | :-: |
|   3   | -3  |
|  4-5  | -2  |
|  6-8  | -1  |
| 9-12  | +0  |
| 13-15 | +1  |
| 16-17 | +2  |
|  18+  | +3  |

[Constitution Modifier]

</div>

-   When damage is taken, HP is lost.

#### Dying

-   Monsters and NPCs usually die at 0 HP.
-   When a PC drops to 0 HP or lower, they must **Save vs Death** at the beginning of each round of combat.
    -   On a success, they can move at half rate this round.
    -   On a fail, they lose 1 HP to blood loss and can't move this round.
    -   While a PC is at 0 HP or lower:
        -   They can't attack or cast spells.
        -   Anyone else may make an INT check to try and stabilize them.
            -   A success raises them to 1 HP and restores their ability to move and fight.
            -   Can't be used on oneself.
    -   At -(level) HP (or lower), they must **Save vs Death** or die.

#### Healing

-   After each long rest (8+ hours of sleep), regain 1 _hit die (HD)_ worth of HP.
-   Once per day, take a short rest (10 minutes) and eat a ration to regain 1 HD worth of HP.
-   Drinking certain potions can restore HP:
    -   A potion of healing restores up to 1d6+1 HP.
    -   A potion of greater healing restores up to 2d6+2 HP.
    -   A potion of supreme healing restores up to 3d8+3 HP.

### Knowledge

-   Spellcasters may make an INT check to identify a magic item.
    -   Failures cannot be re-attempted until research is performed or a level is gained.

### Languages

-   Anyone who speaks a language can understand other related lanuages (ex: dialects) with a successful INT check.
-   Some orders and guilds (especially those that engage in illegal / immoral acts) may teach their members secret or otherwise coded language.
-   The following lists of languages are not all-inclusive.

#### Alignment Languages

Assumed to shared by all (intelligent) members of a given alignment.

-   **Chaotic**: Alignment language of chaos.
-   **Lawful**: Alignment language of law.
-   **Neutral**: Alignment language of neutrality.

#### Class Languages

Most class languages are secret, known only to members of their class, and often include coded terms and/or physical motions (hand waves, knocks, etc.).

-   **Assassin's Cant**: Secret (and coded) language known to all thieves.
    -   Dialects are based on different guilds.
-   **Corsair's Cant**: Secret (and coded) language spoken by all Corsairs.
    -   Dialects are based on different ship / locations.
-   **Druidic**: Secret language spoken by all Druids.
-   **Thieves' Cant**: Secret (and coded) language known to all thieves.
    -   Dialects are based on different guilds.

#### Racial Languages

-   **Aerian**: Native language of air elementals, dialect of elemental.
-   **Angelic**: Native language of angels (law elements), dialect of both lawful and elemental.
-   **Aquon**: Native language of water elementals, dialect of elemental.
-   **Demonic**: Native language of demons (chaos elements), dialect of both chaotic and elemental.
-   **Doppleganger**: Native language of dopplegangers.
-   **Draconic**: Native language of most intelligent reptilian races (kobolds, troglodytes, lizardfolk, dragons, dracokin, etc.).
-   **Duncommon**: Native language of those that dwell deep underground and other dark places (Drow, Medusa, etc.).
-   **Dwarfish**: Native language of dwarves.
-   **Elemental**: Spoken by all elementals, each subtype has their own dialect.
-   **Elvish**: Native language of elves, dialect of faerie.
-   **Faerie**: Native language of the fae, usually divided into 2 dialects:
    -   **High Faerie** Spoken in the ruling courts of the Faewolde.
    -   **Low Faerie**: Spoken everywhere else in the Faewolde.
-   **Farspeak**: Language of the far realms.
-   **Gargoyle**: Native language of gargoyles.
-   **Giant**: Native language of giants.
-   **Goblinoid**: Native language of most intelligent goblinoid races (boggarts, bugbears, goblins, hobgoblins, etc.)
-   **Gnollish**: Native language of gnolls.
-   **Gnomish**: Native language of gnomes.
-   **Greyok**: Native language of several intelligent mammalian animalkin races (Elekin, Hippokin, Rhinokin, Taurokin).
-   **Halfling**: Native language of halflings.
-   **Orcish**: Native language of ogres and orcs.
-   **Pyrean**: Native language of fire elementals, dialect of elemental.
-   **Strallan**: Native language of the Stral and official language of the Stral Empire.
-   **Terrun**: Native language of earth elementals, dialect of elemental.

<div class="dividedTableWrapper">

|  INT  | Spoken Languages | Read? |
| :---: | :--------------: | :---: |
|   3   | Native (broken)  |  No   |
|  4-5  |      Native      |  No   |
|  6-8  |      Native      | Basic |
| 9-12  |      Native      |  Yes  |
| 13-15 |    Native + 1    |  Yes  |
| 16-17 |    Native + 2    |  Yes  |
|  18+  |    Native + 3    |  Yes  |

[Languages Known]

</div>

### Perception Checks

Generally, perception can be checked by rolling highest of INT or WIS.

### Size

A creature's size is usually defined by one of the following categories based on its height and/or weight:

<div class="dividedTableWrapper">

|    Size    | Max Height |  Max Weight  | Control Radius |
| :--------: | :--------: | :----------: | :------------: |
| Diminutive |     1'     |     1 lb     |       1'       |
|    Tiny    |     2'     |    8 lbs     |      2.5'      |
|   Small    |     4'     |    60 lbs    |       5'       |
|   Medium   |     8'     |   500 lbs    |       5'       |
|   Large    |    16'     |   4000 lbs   |      10'       |
|    Huge    |    32'     |  32,000 lbs  |      15'       |
| Gargantuan |    64'     | 250,000 lbs  |      20'       |
|  Colossal  |    65'+    | 250,001+ lbs |      30'       |

[Creature Sizes]

</div>

### Time

Time is often represented at different scales:

-   A combat round is 10 seconds long.
-   An exploration turn takes 10 minutes.
-   A watch takes 4 hours.
-   A long rest takes 8 hours.

<!--
### Usage Die

Some equipment (including many magic items) have limited uses, tracked via a **Usage Die**.

-   The item description will indicate the starting die type.
-   After each use, roll the current die, and on a 1-2, the die drops one step (d20 -> d12 -> d10 -> d8 -> d6 -> d4 -> 1) as uses are consumed.
    -   After dropping a die step from a d4, the magic item has only 1 use remaining.
-   When no more uses are left, the item becomes inert.
-   At the referee's discretion, it may be possible to recharge some magic items, increasing the usage die via complex magic rituals.
-->

!!!include(license/wotc-cc-by.md)!!!