The Blood Moon is a moon that rises infrequently but when it does it marks occasions of intense warfare. Often associated with goblin raids when their lands empty of all goblin-folk in a maddening blood-lust to kill any before them.
The Blood Moon is unique in that it rises during a Hollow Moon phase. It appears on a cycle of 55 years and 5 months.
When the moon appears in the night's sky it's known as a Red Year.