I have found that I have settled on a few MOSAIC strict ways to handle some aspects of OSR/NSR/D&D/Elfgame play, and decide to compile them all here to reference in the future.

Acknowledgements

  • Goblin Punch by Arnold K, for THE UNDERCLOCK.
  • Delta’s D&D Hotspot for castle construction rules (cost and time).

Combat

Morale: Check morale at first casualty and again when a side takes 50% casualties. PCs and the undead never need to check morale. Morale is usually based on the combatants experience level, per the table below.

Experience Morale Roll to Rout Examples
Green 6+ Conscripts, levy
Trained 7+ Militia, town guards
Veteran 8+ Experienced fighters
Elite 9+ Knights, house guards

Fleeing If the monster is not surprised, and the party tries to flee, the monsters may give chase if the reaction roll indicates it. To successfully flee from a pursuer, the fleeing characters must each make a roll of 5+ on a d6. Encumbered characters have -1 on this roll. Unarmored characters have +1 on this roll. Failure means the monster catches up, and resumes its attack.

Distractions Food will always distract unintelligent monsters from the chase, by dropping 1 day’s ration per monster level. Treasure will always distract intelligent monsters from the chase, by dropping 100sp worth of treasure or coins per monster level. Passing through a secret door will always evade a pursuer.

Healing: Restore some health immediately after a fight. Heal some more health and recover all spells with a night’s rest. Heal fully with a week’s rest in town.

Dungeon Delving

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

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
  • 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.

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.

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 5+. 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 lockpicking attempt (5+) to open. A failed lockpicking attempt means that the lock is jammed and cannot be picked again, but does not alert the room’s occupants.

Secret Doors: Secret doors can be discovered by spending a turn 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 are activated on a roll of 1 or 2 on a d6. They can be detected by spending a turn searching the area. Thieves 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.

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.

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

Spell list

  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 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 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 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

At 9th level, a character can begin ruling their own domain. This might take the form of a fortress or manor house and its accompanying village for a fighter, a secluded tower or hut for a mage, or a criminal or mercantile enterprise for a thief.

Fighter’s Manor

Manors consist of the lord’s residence (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, on average, 9 households.

Fortifications take a number of weeks to build equal to sqrt(cost). See table below for details.

Fortification Type Cost (coins) Time
Tower 12,000 100 wks, or 2 years
Keep 80,000 280 wks, or 5.5 years
Castle 420,000 650 wks, or 12.5 years

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 8-10%; higher taxation rates are possible but require a 2d6 roll to avoid an uprising. (This tax rate can be rounded to one-coin-in-twelve for ease of calculating yearly and monthly revenue).

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

Table: Peasant Uprisings

Peasants can provide one (1) levy (as light foot, 1HD, morale 6+) 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 morale roll each week to see if they return to their farms regardless.

Wizard’s Tower

Thief’s Enterprise

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.