Adapting the Stress rules from Liminal Horror or Mothership.
When confronting horror and incomprehensible experiences, characters make a Wisdom saving throw. DC varies on threat. On a fail, the character earns 1 Stress. When a character’s Stress exceeds the character’s Wisdom score, the character suffers a Panic Response.
Examples of Stress
* 1 Stress: Witnessing something horrid. Unexpectedly finding a dead body. Graphic violence in real life.
* 1d6/2 Stress: Witnessing horrific scenes or weird alien vistas. Unexpectedly finding the dead body of a loved one. Brutal graphic violence in real life. Seeing a minor eldritch horror (Hit Dice 1 to 3).
* 1d6 Stress: Witnessing the death of a loved one. Meeting someone you know is dead. Awakening trapped in a coffin. Seeing a major eldritch horror (Hit Dice 4 to 9).
* 3d6 Stress: Undergoing torture. Seeing a monstrous eldritch horror (Hit Dice 10 or more).
Panic Responses (1d20)
* 1 … Severely Traumatized. You suffer the same effects are Shattered plus suffer 3d6 psychic damage.
* 2 to 4 … Traumatized. You suffer the same effects are Shattered plus suffer 1d6 psychic damage.
* 5 to 9 … Shattered. For 1d6 rounds, you are Incapacitated, can’t take any action, Bonus Action, or Reaction, but your movement is not hindered. Your Concentration is broken. You can’t speak. If you’re Incapacitated when you roll Initiative, you have Disadvantage on the roll. If you suffer further Stress failures, roll on this table again.
* 10 to 14 … Frightened. For 2d6 rounds, your base survival instinct takes over. You have Disadvantage on ability checks and attack rolls while the source of Stress is within line of sight. You can’t willingly move closer to the source of fear. If you suffer further Stress failures, roll on this table again.
* 15 to 19 … Exhausting Adrenaline Surge. You gain the benefits of Adrendaline Surge noted below, but when the bonuses end, you gain +1 level of Exhaustion when the surge subsides. If you suffer further Stress failures, roll on this table again.
* 20 … Adrenaline Surge. Your “flight-or-flight” survival instinct takes over. You gain Advantage on attack rolls and +5 feet Speed for 1d6 rounds, after which these bonuses end. If you suffer further Stress failures, roll on this table again.
Relieving Stress
During a short rest, you may make a Wisdom saving throw against a DC equal to your current Stress points. If successful, you reduce your Stress by your Wisdom modifier (at least one). If you fail, you gain 1 Stress point.
At the end of a long rest, you automatically reduce Stress by your Wisdom modifier (at least 1).
A character doubles the number of possible Stress points reduced during a rest by also engaging in some form of dissipation: Revelry, debauchery, consensual sex, drinking, or otherwise doing some form of self-indulgent escapism.