Fear is the core underlying mechanic to Gehenna. It affects players through both narrative and gameplay, by weakening the player down and testing their resolve under high stress.

Fear is gained through many different facets according to the Gamemaster. Many attacks give Fear, and player Phobias will give further Fear through contextual situations. In some phobia instances, Fear gained may even be multiplied.

Fear attacks 2 meters: Physical, and Mental fear. These add together to make a players Mind. Small unsettling details may slowly attack players Mind without any need for a roll. However, anytime a player is confronted with a significantly terrifying moment, 2D6 is rolled + the according fear stats modifier; Whether the situation is Mentally or Physically frightening. If the roll is higher than the DC, then the player either takes halved damage to their Mind, or no fear depending on the context. Snake eyes will always result in no fear gained.

When a players Mind reaches 0, their resolve is tested. 1D20 is rolled, and the outcome will result in:

20: The player receives a Trait.
19: The player gains a Phobia.
12-18: The player gains a Foible.
5-11: The player gains a Flaw.
2-4: The player gains a Flaw and Phobia.
1: The player gains a Flaw and Phobia, and lose 1 point of Composure.

Afterwards, the player's Mind will be reset back to full capacity.