The Blood Moon is a night-time event that is characterized by an unusually large assault of enemies which occurs roughly every five days, the first of these guaranteed to occur on day V. During a Blood Moon, the sky and the moon both acquire a red hue, with ominous ambiance and music accompanying the changes, often catching a newer player unaware if they've never experienced the event before. Unlike regular nights, where monsters can attack from both sides, the Blood Moon attack happens only from one side.
Blood Moons are usually preceded by rainy or cloudy weather, as well as being fairly predictable by the sequential pattern in which they normally occur. The first Blood Moon (on day V) features only high amounts of regular Greed monsters. The third Blood Moon (usually on day XV) will usually include Floaters, and on the fifth Blood Moon (usually on day XXV), Breeders join in the attacks as well. The attacks scale in number over time, much like regular attacks, making it a formidable challenge to overcome in later days, particularly after day XXX.
The day immediately following a Blood Moon attack is a perfect opportunity to seize a Portal, as the Portal exhausts its resources to fuel the Blood Moon and will shut down for the subsequent day. This prevents an attack from that Portal the next night, leaving it vulnerable and unprotected during that night.
- As of the Kingdom 1.2 Beta, rare occasions can see multiple blood moons in rapid succession. This feature persists into the New Lands expansion.
- As of the Kingdom 1.2 Beta, there has been rare occurrences of Blood Moons not following the 5-day pattern. This feature persists into the New Lands expansion.