"When the moon shines red as scarlet blood, gods shall fall to ash and mud."
A Blood Moon is an extremely rare occurrence, feared by the Sorcerers and Deities alike. Fulfilling a prophecy that dates back to the age of Eden, all powers of Magic have no effect during a Blood Moon, and all magical artefacts, constructions, and spells are completely ineffectual. Even Elementals are trapped in their human forms and unable to use magic of any kind.
Blood Moons arrive without warning and last for seven days and seven nights, during which most Secrets retreat to their halls and barricade themselves inside. Thankfully, even Others are weakened during this period, and unable to manifest through rifts torn into the fabric of reality or use their abilities if they are already manifested in the mortal realms.
However, Blood Moons are not a time for rest and recuperation, for the fighting goes on... while most types of magic are completely cancelled by the presence of a blood moon, the powers of occultism are increased tenfold, and covens of occultists creep from the shadows to warp or change the world as they see fit.