Also called the Purple Moon, the Necromancer Moon or the Pale Moon
One of the Nine Moons in the heavens, it represents the forces of Undeath. It only is visible for three days every 74 years, 6 months and 16 days (24,154 Days)
The coming of the Purple Moon is well-calculated and many villages know, to the date, when the Purple Moon is scheduled to rise. Nobles will send heralds to each of their villages to warn of the impending doom so that they can lock themselves and their livestock up and remain indoors for the duration of the moon's effect.
Thankfully, the moon's sway only works at night. Each morning during the three days of the Purple Moon, villagers will fan out around their homes to look for any sign of undead. If any are found they will usually be put to the torch so that they don't rise by the next night.
Traveling is restricted during the year when a Purple Moon is predicted - most people won't leave their homes for long for fear of being caught out and unprotected. Wars and battles are put on hold during the 'Purple Year' for fear that the dead on the battlefield might rise up against one or the other side - or both.
See also: Purple Year