A Blood Moon is a very rare natural phenomena, in which the moon appears larger than normal, and takes on an ominous, red color. Celebrated in some parts of the world, feared in others, it does not seem to have any effect on the normal proceedings of the world.
However, Werewolves are an exception to this.
When a Blood Moon rises, werewolves have been known to show effects, which vary from individual to individual. Some claim enhanced senses, a small increase to power, while others may feel anxious, or even ill during one, but all of these are rare and in most cases the event will have no effect on a werewolf at all.
It must be stated though, there is an exception to this exception.
Werewolves of the Great Wolf Strain are severely affected by it, 100% of the time. A Blood Moon causes them to enter their Great Wolf Form, and enter a rage very similar to that of Berserker Strains. Given the drastic increase in their power, they are almost unstoppable during this night, and heavy precautions must be enforced so they do not harm others. A werewolf of this strain will show signs of discomfort the moment dusk falls, and while the time of their transformation varies on the willpower and control of each individual, getting through the night without transforming seems virtually impossible.