The Planar Vagabond's Guide to the Multiverse

Heroic Old-School Roleplaying
Core Rules: Adventuring

Introduction

In general, playing an RPG powered by HOSR comes down to running through a series of linked procedures or “game loops” (ex: Exploration Procedure):

1. Setup: GM determines the current situation (often using dice and tables), and describes it to the players.
2. Response: Players explain how they want to react to the situation, and make any checks that the GM calls for.
3. Repeat" Return to step 1 and repeat until the adventuring ends.

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

Then, check the results of the roll:

• A natural 20 or a result of 25 or more is a Critical Success: the check succeeds, and often includes a bonus for the roller.
• An 11-24 indicates a Complete Success: the check succeeds.
• A 6-10 represents a Complicated Success: the check succeeds, but with a potential complication or challenge for the roller.
• A 5 or less is a Failure: the check fails.
• A natural 1 or a result of less than 0 is a Fumble: the check fails, and often includes an extra complication or challenge for the roller.

Skilled Ability Checks

Many classes have unique skills which PCs learn as they gain levels in those classes.

When making a check that involves a class skill, add the skill modifier for the PC’s current level to the appropriate ability check roll.

• ex: a 5th level thief that wants to use their Thief Skills to hide in the shadows would make a DEX ability check, rolling a d20 and adding their DEX modifier to the roll, and would then add an additional +1 to the roll before determining the result.

Complications

Complications can effect the immediate situation or the GM can optionally save them for later, tallying or counting them, and making a Complication Check for each one at the next appropriate time.

Complication Check

Roll 1d6.

• Encounter: Wandering creature, social encounter, or some other random interaction.
• Locality: Some environmental or external event that affects the PCs.
  • ex: a storm rolls in, party gets lost, the dungeon shifts, water rises, the assassin gets closer to the target, doors lock behind party.
• Exhaustion: Party must rest for a turn / watch or gain a level of exhaustion.
  • May be ignored for the first few checks in a session, as appropriate.
• Signs / Portents: Indications of possible encounter nearby - could be a clue, monster tracks, etc.
• Discovery: Party finds something useful or helpful.
  • ex: a magic item, a secret door, a hidden ally.
  • May be ignored after first occurrence in a session, as appropriate.

Exploration Procedure

The time scales for exploration vary based on the area being explored:

• Dungeon exploration is divided into 10-minute turns, with each turn covering roughly 180 feet of unexplored dungeon.
• Wilderness exploration is divided into 4-hour watches, with each watch covering roughly 6 miles of unexplored (open) terrain.

The general steps to take when exploring (for each turn / watch):

1. Setup: GM describes the situation.
2. Marching Order: Party determines general exploration process, including direction of travel and speed.
3. Complication Check: GM rolls the complication die to see what effect it has.
4. Actions / Responses / Complications: Party declares actions, GM 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.
6. Repeat: Return to step 2 and repeat until adventuring ends (or destination is reached).

Challenges and Hazards

• Fall damage is 1d6 per 10’.

Darkness

• If unable to see, treat as blinded.
• Candles light 10’ radius.
• Torches / lanterns light 30’ radius.
• When moving through darkness with flame light, no chance of stealth / surprise.

Infravision

Allows creatures to see heat tones, even in darkness.

• Works to 60’ unless noted otherwise.

Truesight

Allows creatures to:

• see in normal or magical darkness;
• see invisible creatures and objects;
• automatically detect, see-through, and Save vs visual illusions;
• perceive the true (original) form of a shapechanger or ploymorphed creature; and
• see into the ethereal plane to perceive ghosts and other spirits.

Listening for Noises

Spend a minute listening (ex: at a door) and make an INT or WIS check to hear a noise.

• GM rolls.

Opening Doors

• Locked Doors can be picked or broken.
  • Picking a lock takes up to 1d6 minutes.
• Stuck Doors can be unstuck or broken.
• To unstick or break a door, make a STR check at -2.
  • Doors always break on a critical success.
  • Failure / complications can affect stealth / surprise.

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

• Each combat round, a drowning creature must Save 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 an Urban Exploration 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.

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 creature (ex: elephant)

Light

• During the daytime, fog or heavy rain will create dim light in open areas.
• At night:
  • A full moon on a clear night will create dim light in open areas.
  • Fog or moonless night will create darkness.

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:

  • Maintained 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.

• 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.

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: GM 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.
     • Individual party members may have stealth even if the rest of the party doesn’t.
   • 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: GM 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.

   • Tie goes to the party side, roll-off as needed.

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 encoulastnter itself, but may be determined randomly.
     • If creature / NPC reaction isn’t obvious, make a Reaction Roll (2d6, possibly modified based on what the creature / NPC believes about the party beforehand).
     • If someone tries to communicate, make a 2nd reaction roll, this time modified by the speaker’s CHA modifier and a modifier based on the first roll as indicated below.

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 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.
  • GM 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, the PCs will interact with their world, gaining Level Points for each session.

• Once a PC acquires a number of Level Points equal to their next desired level, they may gain a level in their desired class.

Upon Gaining a Level

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

• Roll a hit die (based on the class), and add it to their maximum hit points.
  • 1s and 2s may be re-rolled a single time.
• Check the Skilled Ability Check Modifier table to determine if their skill modifier increases.
• Check the PC’s class and race to see if they gain any new.
• The 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.

Creature 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.

Entangled

• An entangled creature:
  • is unable to move,
  • has disadvantage on attack rolls and ability checks that require moving,
  • can make a new Save attempt each combat round,
  • is automatically released if the entangling weapon is used to attack another opponent.
• Attack rolls against an entangled creature have advantage.

Exhausted

• An exhausted creature:
  • gets -1 to all rolls, and
  • has their AC reduced by 1.
  • These effects are cumulative for each level of exhaustion they have.
• Each level of exhaustion can be cleared by resting for 4 hours (1 watch).
• Going for more than one day with a long rest adds 1 level of exhaustion per day since last long rest.

Frightened

• A frightened creature:
  • is unable to willingly move closer to the source of its fear (desiring only to flee from it), and
  • has disadvantage on ability checks and attack rolls while it can see the source of its fear.
• Most unintelligent creatures will actively flee when frightened.

Invisible

• An invisible creature:
  • can’t be seen without magic or a special sense (ex: Truesight),
  • 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 and can only be made when attacking creature has some idea of where the invisible creature is (or recently was).

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.
  • Optionally, the GM 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), and
  • has disadvantage on attack rolls.
• When attacking a prone creature:
  • melee attacks have advantage, and
  • ranged attacks have disadvantage.

Restrained

• A restrained creature:
  • is unable to 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 unable to move, attack, take any actions, and can speak only falteringly; and
  • automatically fails any ability check that requires movement.
• Attack rolls against an stunned 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.
  • Optionally, the GM 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), with a minimum of 7.
  • Additionally, characters may carry a number of packed items up to their Strength (STR), also with 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:

• When damage is taken, HP is lost.

Dying

• Creatures and NPCs usually die at 0 HP.
• When a PC drops below 0 HP, they are momentarily stunned until they Save at the end of their next initiative turn.
  • The Saving throw is modified as follows:
    • the PC’s CON modifier is applied to it,
    • -1 for each HP bellow 0, and
    • +1/2 current level (round up).
  • On a success, the PC stabilizes at 0 HP.
  • On a fail, the PC can give some potential final words before falling unconscious, apparently dead.
• While a PC is stabilized at 0 HP, they:
  • can only move 1/2 their normal rate,
  • can’t attack or cast spells, and
  • can make an INT check and try to restore their mobility.
    • The check counts as a combat action.
    • On a full success, the PC heals to 1 HP and can move and attack as normal.
    • On a complicated success, the PC remains at 0 HP.
    • On a failure, the PC drops to -1 HP and is momentarily stunned until they Save at the end of their next initiative turn.
• Any other character may make an INT check to try and help a stabilized or stunned PC at or below 0 HP, restoring their mobility.
  • The check counts as a combat action.
  • On a success, the PC heals to 1 HP and can move and attack as normal.
  • On a normal failure, the PC remains at current HP.
  • On a critical failure, the PC loses 1 HP and is momentarily stunned until they Save at the end of their next initiative turn.

Recovering the Body

If the body of an apparently dead PC is recovered, the PC gets one final chance to Save or Die.

• Add CON modifier to roll,
• On a success, the PC sits upright wheezing deeply, having only been winded or wounded, and is restored to 1 HP (able to move and attack as normal).
• On a failure, the PC is well and truly dead - there’s nothing to do but go through their pockets for loose change.

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.
• Quaffing a readied potion takes a combat action, but can be done while moving.

Languages

• Anyone who speaks a language can understand other related languages (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.
• Chitter: The secret language of burrowing mammals, known to many gnomes.
• 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 outside of the ruling courts of the Faewolde.
• Farspeak: Language of the far realms.
• Firbish: Native language of firbolgs.
• Giant: Native language of giants.
• Goblinoid: Native language of most intelligent goblinoid races (boggarts, bugbears, goblins, hobgoblins, etc.)
• Gnollish: Native language of gnolls and jakkra.
• 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.

Perception Checks

Generally, perception can be checked by making either an INT or WIS check.

Size

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

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.

Legal Information

This work includes material taken from the System Reference Document 5.1 (“SRD 5.1”) by Wizards of the Coast LLC and available at https://www.dndbeyond.com/srd. The SRD 5.1 is licensed under the Creative Commons Attribution 4.0 International License available at https://creativecommons.org/licenses/by/4.0/legalcode.