These are my house rules for running DnD-like games.

Acknowledgements

Character Creation

Start with the following:

  • 3d6 STR
  • 3d6 DEX
  • 3d6 WIL
  • 1d6 HP
  • Roll a d6 on the table below for each column to determine the rest of your starting gear:
d6 Armor (+1 to roll if STR is >12) Weapons (+1 to roll if DEX is >12) Gear (+1 to roll if WIL is >12)
1 None Staff (d6, bulky) & Sling (d4) Hammer & Spikes (6)
2 None Mace (d6) & Shield (+1 Armor) Torches (3) & Tinderbox
3 None Daggers, two (2d4) Shovel & Pickaxe
4 Padded (1 Armor) Axe (d6) & Shield (+1 Armor) Rope, 50 ft
5 Padded (1 Armor) Spear (d8, bulky) Lockpicks
6 Padded (1 Armor) Bow (d8) & Arrows Mule
7 Chainmail (2 Armor, bulky) Sword (d8) Random spellbook (roll d20)

Saving Throws

When doing something risky, a character must make a save by rolling a d20 under the appropriate ability to succeed.

  • STR for tests of strength or endurance.
  • DEX for tests of agility or precision.
  • WIL for tests of concentration, battles of will, or interactions with magic.

Experience & Advancement

Gain 1 XP for every sp spent on carousing, partying, donating, gambling, or other pursuits without material reward. Slaying monsters may award XP as well, but this is significantly more dangerous and less rewarding than stealing treasure.

When a character gains a level, do the following:

  1. Roll 1d20 for each ability score. If it is greater than or equal to the ability score, increase that score by 1.
  2. Increase HP by +1
Level XP
1 0
2 2,000
3 4,000
4 8,000
5 16,000
6 32,000
7 64,000
8 128,000
9 256,000

Table: XP & Levels

Equipment & Encumbrance

Characters can choose how encumbered they are, and what they are encumbered with, from the following options:

  1. Unencumbered - The character is only carrying their fighting kit (weapons, armor, spellbook, holy symbol, thieves tools, etc) and a few personal trinkets (magic rings, treasure map, anything that can be stuffed into a pocket).
    • Benefits: Always act before monsters (don’t need to make a DEX save).
    • Drawbacks: None.
  2. Encumbered with Supplies - The character is carrying their fighting kit, trinkets, and a backpack full of supplies (rations, waterskins, torches, iron spikes, rope, etc).
    • Benefits: Can carry 2 weeks of supplies for wilderness travel, and reduces the amount the Dungeon Clock decreases each turn by 1 (meaning a 1d6-1 is rolled instead of 1d6).
    • Drawbacks: Must succeed on a DEX saving throw to act before monsters.
  3. Encumbered with Treasure - The character is carrying their fighting kit, trinkets, and a backpack full of treasure (gold coins, gemstones, jewelry, statuettes, etc).
    • Benefits: Can spend the treasure for 2d6x100 sp in town.
    • Drawbacks: Must succeed on a DEX saving throw to act before monsters.
Type Armor Cost (sp)
Unarmored 0 -
Shield +1 10
Padded 1 30
Chainmail 2 100
Plate 3 1000

Table: Armor & Encumbrance

Note: Combined Armor from all sources cannot exceed 3.

Weapon Damage Cost (sp) Notes
Unarmed d4 -  
Dagger, Club, Staff, etc d6 10  
Sword, Mace, Axe, Spear, etc d8 50  
Poleaxe, Longsword, etc d10 100 2H
Sling d4 10  
Bow d6 25 2H
Crossbow d8 50 2H

Table: Weapons

Note: 2H weapons must be wielded in two hands.

Transport Cost (sp) Carrying Capacity Notes
Mule 30 2x men WIL 10
Horse, Riding 60 2x men WIL 8
Horse, War 150 3x men WIL 12, requires double feed
Ox 100 6x men WIL 6
Cart, hand 5 2x men  
Cart, draft 10 2x beast pulling it  
Wagon 30 4x beast pulling it  

Table: Transportation

Note: Feed consumed per day assumes freely available water and forage (such as grass or other undergrowth).

Basic Combat

Reaction Rolls: When encountering a wandering monster or other entity, and their disposition is unknown, roll 2d6 to determine their reaction.

2d6 Reaction
2- Hostile
3-5 Negative
6-8 Uncertain
9-11 Positive
12+ Enthusiastic

Table: Reaction Roll Results

Initiative: Characters must make a successful DEX save to gain the initiative and act before their enemies. On each of their turns, a character may move a short distance and take one other action, such as:

  • Move further
  • Attack
  • Interact with an object

Attacking: To attack, roll your weapon’s damage die, and subtract any Armor that your target possesses. You deal that much damage to your target’s HP.

Critical Damage: Damage that reduces a target’s HP below zero decreases a target’s STR by the amount remaining. They must then make a STR save to avoid critical damage.

  • Any PC that suffers critical damage cannot do anything but crawl weakly, grasping for life. If given aid and rest, they will stabilize. If left untreated, they die within the hour.
  • Additionally, some enemies will have special abilities or effects that are triggered when their target fails a critical damage save.

Advanced Combat

Enhanced & Impaired: If your attack is enhanced, increase the die size by one step. If it is impaired, decrease the die size by one step.

Multiple Attacks: If multiple damage dice are rolled against the same target (whether by dual wielding, multiple attackers, etc), only the highest result deals damage.

Charge: In the first round of combat, a combatant may charge an enemy by moving from outside of melee range to within melee range of an enemy in the movement phase. The charging combatant deals enhanced damage on their next attack against the charged enemy.

Blast: Attacks with the blast quality affect all targets in the noted area, rolling separately for each affected character. If unsure how many targets can be affected, roll the related damage die for a result.

Stunts: A combatant can choose to trip, disarm, blind, or otherwise perform a dirty trick on his opponent. He makes an attack as normal. His opponent can choose to take damage as normal, or suffer the effects of the combat manuever.

Morale & Fleeing

Morale: Enemies must pass a WIL save to avoid fleeing when they take their first casualty and again when they lose half their number. Some groups may use their leader’s WIL in place of their own. Lone foes must save when they’re reduced to 0 HP. Morale does not affect PCs.

Undead are always hostile, never check morale, and normally cannot be reasoned with (intelligent undead such as liches or vampires are an exception).

Flee: Running away from a dire situation always requires a successful DEX save, as well as a safe destination to run to. If you are mounted and your pursuers are not, you automatically succeed at fleeing.

Distraction: Food will always distract unintelligent monsters from the chase, by dropping 1 day’s ration per monster. Treasure will always distract intelligent monsters from the chase, by dropping 100sp worth of treasure or coins per monster.

Secret Passages: Passing through a secret door will always evade a pursuer.

Death & Healing

If a PC’s STR is reduced to 0, they die. If their DEX is reduced to 0, they are paralyzed. If their WIL is reduced to 0, they are delirious.

Ability scores and HP are restored by resting:

  • Short rest: Takes a few minutes in a safe, well-lit area. Heal all HP.
  • Long rest: Takes a night in camp and a ration. Heal all HP and heal d6 of one ability score.
  • Full rest: Takes a week in town and paying for room and board (usually 20sp). Heal all HP and all ability scores.

Dungeon Delving

The Clock: When you enter the dungeon, the clock starts at 20 (use a spindown d20 from MtG for this). Each turn, roll 1d6 and subtract the result from the clock. When the clock hits 0, a wandering monster is encountered and the clock resets to 20.

Turns: One turn of dungeon exploration takes about ten minutes, and generally allows the party to take one action, such as:

  • Open a stuck or locked door
  • Search the room thoroughly, revealing traps and secret doors
  • Take a short rest
  • Interact with a feature of the room, such as a trap
  • Move to the next room

Darkness: When the party does not have a light source, 2d6 is rolled against the dungeon clock each turn instead of 1d6, and they are unable to find traps or secret doors regardless of time spent searching.

Light Sources: Torches, candles, lamps, or the like require a free hand to hold them. One such light source is required for every 4 dungeon explorers.

Fleeing the Dungeon: When the party flees back to camp in disarray (as opposed to an orderly withdrawal), each character must make a save against DEX and WIL. If the DEX save is failed, they lose 1d6x10% of treasure obtained. If the WIL save is failed, they take 1d6 WIL damage.

Doors

Hear Noise: Characters can listen at doors and attempt to hear if the room is occupied. Note that the undead make no sound.

Forcing Doors: All doors are stuck and must be burst open by force with a successful STR save. A failed attempt means you still burst open the door, but it makes surprising whatever is behind the door impossible.

Locked Doors: Some doors are locked, and require a key or a successful DEX save to pick the lock to open. A failed lockpicking attempt means that the lock is jammed and cannot be picked again.

Secret Doors: Secret doors can be discovered by searching the room.

Spiking Doors: Doors will open freely for monsters and swing shut of their own accord, unless wedged with iron spikes. When wedged shut, monsters must attempt to burst the door open as above, possibly giving the party time to hear them coming. Doors can also be wedged open with spikes, to ensure the party a clear path of escape.

Holding Doors: Sometimes (especially during a chase) the party will try to hold a door against pursing monsters. The side trying to force a held door must try to burst it open as normal.

Traps

Room Traps: Room traps are activated on a failed DEX save. They can be detected by spending a turn searching the area. Characters can attempt to disarm traps; but be careful, as a failure will trigger the trap. If the character doesn’t want to risk this, find a clever way to bypass the trap. Traps deal damage directly to an ability score on a failed save.

Treasure Traps: Treasure traps such as locks with poison needles, or a weighted plate underneath a statuette, can only be detected by spending a turn searching the treasure. Characters can attempt to disarm them, but failure will trigger the trap. Traps deal damage directly to an ability score on a failed save.

Tunnelling

One man can move a 5x5x5ft cube of dirt every 2 hours, or the same volume of rock every 4 hours. The appropriate tools such as pickaxes and shovels are required.

Tunnels can be crawled through slowly if they measure 5x5ft, or walked through normally if they are 10x10ft.

Wilderness Travel

Wilderness travel turns take place over turns of one day in length. Each day, the party may take one of the following actions:

  • Move 2d6+8 miles towards another area
  • Hunt, fish, or forage for d3 rations of food or water (natural features permitting)
  • Explore the current area to reveal landmarks
  • Travel within the current area to a discovered landmark

Spellcasting

Spellbooks contain a single spell. Anyone can cast a spell by holding a spellbook in both hands and reading its contents aloud.

Spell Level: A spell’s effective caster level is equal to the amount of WIL damage the caster inflicts upon himself. This WIL damage can be healed with rests just as with any other ability score damage. The max spell level is 6th (and thus max WIL damage that can be inflicted this way is 6 damage).

Scrolls are similar to Spellbooks, however they burn to ash after one use, and are always cast at 1st level.

Casting: Unless otherwise specified, spells take 1 action to cast and require two free hands.

Duration: Unless otherwise specified, spell effects last for 10 minutes per spell level.

Counterspells: Any spellbook may be cast as a counterspell instead of it’s normal spell. A counterspell protects one person per spell level from the effects of one spell.

Spell Descriptions

  1. Animate Dead: Animate a number of undead equal to spell level. Roll d6 when spell ends: (1-3) undead become hostile, (4-5) undead collapse into dust, (6) undead serve the caster permanently.
  2. Augury: Perform a divination to determine whether a given course of action will result in “weal” or “woe”. The caster may ask one question per level. DM rolls a d6 secretly: on a 4+, the answer is truthful. Sacrifice 1d6 STR in blood to guarantee a truthful answer.
  3. Charm: Hostile creatures become neutral, neutral become friendly, and friendly creatures become infatuated. Affects a number of creatures equal to spell level.
  4. Circle of Protection: Draw a circle on the ground with chalk, salt, or blood. Undead, fey, demons, or other unnatural creatures cannot cross the boundary. Protects one creature per spell level.
  5. Control Weather: Control the weather, causing clear skies, storms, winds, etc as desired. Effects last for 1 day per spell level.
  6. Dominate: Release control of your own body and domineer that of a nearby creature. Subject saves to prevent.
  7. Fireball: Deals 1d6 fire damage per spell level to all targets in a small area (such as a melee or a room). Targets save for half damage.
  8. Fly: Fly at walking speed. Affects one creature per level. Spell is reliable for 10 minutes per spell level, then has a chance to end on each subsequent turn on a roll of 5+ on a d6.
  9. Hold Person: Paralyzes a number of creatures equal to spell level. Subjects save to avoid.
  10. Invisibility: Turn one creature per spell level invisible.
  11. Knock: Open one stuck or locked door within arm’s reach.
  12. Lightning Bolt: Deals 1d6 lightning damage per spell level to all targets in a line. Targets save for half damage.
  13. Scry: Requires a mirror, crystal ball, still water, or similarly reflective surface. Remotely see and hear events that are up to 10 miles away per spell level.
  14. Sleep: Puts all within a small area (such as a melee, or a room) into a deep slumber. Subjects save to avoid.

  15. Speak with Dead: Ask 1d6 questions of the corpse of a deceased intelligent creature. Reaction rolls apply and negotiation may be required. Corpse may be dead for a period of time based on spell level…

    Spell Level Deceased for…
    1st 1 week
    2nd 1 month
    3rd 1 year
    4th 10 years
    5th 100 years
    6th 1000 years
  16. Third Eye: You can see all invisible, ethereal, and shapechanged creatures in their true form. You also see the auras of spells (both cast and prepared) and enchanted objects.
  17. Tongues: You can comprehend all written and spoken languages.
  18. Water Breathing: Can breathe under water for 10 minutes per spell level. Affects one creature per spell level.
  19. Wind Barrier: Buffeting winds prevent missile attacks from harming those within. Protects one creature per spell level.
  20. Wizard Lock: Locks one door, chest, window, or similar portal. Requires a knock spell or similar magic to open.

Domains

Manors consist of the lord’s keep (anything from a small fortified house, to an expansive castle, depending on the wealth of the lord) and the accompanying peasant population of the manor. The population density of a manor depends on the region in which the manor is located:

  • Wilderness: d6-3 households per square mile
  • Borderlands: d6 households per square mile
  • Heartland: d6+3 households per square mile

The typical manor for a minor lord is 2 to 3 square miles in size. If this is located in the borderlands, it will thus contain approximately 10 households.

Castles cost ~80,000 coins and take an amount of time to build equal to sqrt(cost), or approximately 5 and a half years for a 80,000-coin castle.

Taxes: Each household generates 1 coin in productive capacity every month. This consists mainly of food, cloth, and labor, rather than pure cash. The peasantry are typically taxed at 10%; higher taxation rates are possible but require a 2d6 roll to avoid an uprising.

Tax Rate Uprising on…
10% happy, no uprising
15% 10+
20% 9+
25% 8+
30% 7+

Table: Peasant Uprisings

Levies: Peasants can provide one (1) levy (HP d4 WIL 7) per household in times of war. Levy will serve for 6 weeks unpaid (though they must be supplied with food, either by their lord or through forage); beyond that, they must be paid wages as mercenaries or they immediately disperse. Even if paid, make a WIL save each week to see if they return to their farms.

Monster Conversion

HP = HD + 3 (default to d6 if unsure)
STR, DEX, and WIL default to 10 each. Increment by +/-4 if particularly strong, brave, agile, etc.
Attacks: Use same die type. Multiple attacks are rolled as normal, but only the highest die deals damage.
Armor: Lightly armored or naturally armored monsters have Armor 1 or 2. Particularly impervious monsters (dragon scales, etc) have Armor 3.
Morale: B/X-style morale scores can be converted to WIL per the following table:

B/X Morale WIL score
2 1
3 2
4 3
6 7
7 9
8 13
9 15
10 18
11 19
12 20

Table: Morale-to-WIL Conversion

License

Creative Commons License
Cairn House Rules by Tyler Farrington AKA Underwater Owlbear is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.