Insanity and Reason

The characters Reason is based on the characters willpower. Insanity chips away from Reason. For every 10 Sanity points gained, the user looses 1 Reason.

When a sanity check is asked by the storyteller, the player will roll his total willpower to try and core with the horrors and madness that is afflicted upon the character.

Roll: Willpower (Resolve + Composure) – Difficult (Determined by GM but never more then 5)

Pass: The player is unfazed by the indecent.

Failure: The character will gain insanity which will chip away from reason. This is determined by what sort of horror the character is up against. For every 10 Insanity gained, the player losses 1 Reason.

If the character losses Reason in this manner, the player must roll his current Reason. A failure means the player will receive a temporary derangement. A botch would mean the player gains a permanent derangement. Some forms of insanity can still cause more insanity and chip away from reason.

If the character drops to 0 sanity, the player may receive a serious derangement. (Taken from the NWod core book or Mage the Awakening)

Ash Can Pete sees a Cthulhu while pan handling in the streets of Innsmouth. Ash Can Pete rolls his willpower (7) – 5 dice (Cthulhu is fuckin scary) but fails to gain any successes. He will gain D100 Insanity due to the horror that is Cthulhu.


The GM rolls a 57. Ash Can Pete has a Reason of 7 and no Insanity. After the deductions, Pete is left with 2 Reason and 7 Insanity.

Now the player rolls his new Reason value and needs to get a success. He rolls one success managing him to stave off any temporary derangement but is weaker willed after the encounter.


All Reason losses are based on Chaosium’s Call of Cthulhu core book and other supplements. Difficulty of Reason loss is based on the die roll found in the books.
D100 – minus 5 dice
D20 – Minus 4 Dice
D10 – Minus 3 Dice
D8 – Minus 2 Dice
D6 – Minus 1 Die

Insanity and Reason

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