Winged Convergence

The Winged Convergence is an astrological event that occurs every forty-seven years (at least in Maradaine). During this time Omali, the White Moon, is at quarter waning and passes behind Namali, the Blood Moon, giving it the appearance of wings.

There is a possible ritual that could be performed at this time. According to the book Brenium's Northern Travels, the Kieran mage Brenium met a mystic claimed that a blood ritual could be performed during the Winged Convergence that could create a creature of pure numina, a jaäbousha. He couldn't do it at that time because he didn't have the proper tools. He needed to be "clad to establish his power, and binding to control the beast."