Stress House Rules:
Each character has a Stress Level. It begins at 0. When encountering something horrifying, mind-bending and sanity-wrecking, a certain amount of points is added to it (usually in the 1-to-5 range).
Characters also have Quirks (they begin with one Negative Quirk, but also gain more throughout the game).
Each Quirk has an associated Save: it’s mostly Wisdom or Charisma (against fear or repulsion), but it can also be Dexterity (against shaky hands) or Constitution (against "Stress Eater"). The current Stress Level sets the DC for Saves against the effects of negative Quirks. If the Stress Level is 10 or less, the Save is passed automatically.
The DM will give cues to evoke the Quirks, but eventually it is the players’ responsibility to role-play their Quirks to the maximum. In every situation where a Quirk is applicable, the player must roll a Save. If the Save fails, apply the effects, either mechanically or narratively.
Some Quirks also have passive mechanical effects, that are always applied (disadvantage on attacks against certain creature types, less damage, etc.).
Bonus experience is awarded for role-playing Negative Quirks consistently.
Example #1: Sigur the Fighter has Fear of Undead (Quirk, associated with Wisdom), and a Stress Level of 12. He encounters a pack of animated skeletons. Without the Quirk, Sigur would charge into battle. But instead, a Wisdom Save must be made, against his current Stress Level. If he passes, he can fight as usual. If the Save is failed, Sigur’s player must role-play the character’s Quirk – Sigur hides, flees, stares in shock, etc., and also receives +1 Stress. On the next turn, the Save can be repeated to overcome the effect.
Example #2: Hildred the Druid is Kleptomaniac (Quirk, associated with Charisma), and has a Stress Level of 15. One of her companions has a silver holy symbol. During rest, Hildred must make a Charisma Save (DC 15), or otherwise try to steal the item.
There are also Positive Quirks. They are rare, but highly effective. If a Positive Quirk is applicable in a game situation, roll the associated Save, against the Stress Level as the DC. But your goal is to FAIL this Save: Positive Quirks are easier to evoke when under great stress.
Example #1: Olga the Ranger is a "Trusty Companion" (a Positive Quirk, with Charisma as the associated save), with Stress Level at 14. Her brother-in-arms is in grave danger. Olga’s player tries to evoke this Quirk, and rolls a Charisma Save. If this save FAILS, Olga gains Inspiration.
Negative quirks:
(If two Saves are listed, the player gets to pick which one to use)
* Claustrophobia (Wisdom or Charisma) - fear of enclosed or crowded areas
* Nyctophobia (Wisdom or Charisma) - fear of darkness
* Thanatophobia (Constitution or Charisma) - becomes cowardly when low on hit points (under 25% of maximum)
* Fear of the Undead (Wisdom or Charisma) - gains more stress and becomes cowardly when facing undead creatures
* Fear of Tentacles (Wisdom or Charisma) - irrational fear of tentacles!
* Stress Eater (Constitution) - consumes double rations during rests
* Nightmares (Wisdom or Intelligence) - during long rests, do not regain all hit points or hit dice. May spend hit dice to heal like during short rests
* Perfectionist (Charisma) - stress increases if misses several times in a row or fails a skill check
* Morbid Curiosity (Wisdom or Intelligence) - will examine weird and potentially dangerous things against better judgement
* Compulsive (Charisma) - suffers intense need to do specific actions
* Bloodthirsty (Wisdom or Intelligence) - finds pleasure or interest in cruelty, might stress out companions
* Unquiet Mind (Wisdom) - vulnerability to psychic damage, weirded out easily by telepathy and other mental magical effects
* Death Wish (Charisma or Constitution) - disadvantage on Death saving throws
* Hallucinations (Wisdom) - sees or feels things that aren't there
* Kleptomaniac (Intelligence or Wisdom) - prone to steal things from companions
* Drunkard (Wisdom or Constitution) - heavy drinker, especially when under stress
