The Guardian Charms are a family of rituals used during the construction of houses. The primary charm involves burying a horse’s skull beneath the door frame, which makes it difficult for certain malevolent spirits (such as vampires) to gain entry to the house unless invited in by an inhabitant. Another is placing a mummified or preserved cat within the walls, which grants a bonus to saves made by inhabitants to resist disease. A third is cutting a pattern of short lines into the beams or supports of a house, which reduces the effects of environmental damage to the building itself. All last for the house’s lifetime except the cat-charm, which must be renewed for each new inhabitant or group of inhabitants.
The base difficulty of each ritual is d6, and automatically costs a point each of strain and fatigue. Extra fatigue and/or strain can be taken by a caster familiar with the ritual (i.e. with skill points invested in it). For each doubling of the energy invested, the charms increase in power: the horse-head charm costs malevolent spirits one point each of strain, fatigue, and health if they cross the threshold uninvited. The cat charm grants an extra +1 to rolls. And the cutting charm reduces damage done by an extra +1. Energy costs can be halved by increasing the difficulty by a step, or doubled to decrease it by a step. As with many such rituals, the working of Guardian Charms often becomes a community event led by the local hedge-wizard or witch-doctor, with each member contributing a modicum of energy.