It has been rumoured that the blood of the light faes were known to be the sweetest, most delicious blood for the vampires. Many vampires in the past, during the time when the Middle Empire was still in its former glory, were obsessed with the idea of tasting a light fae's blood. But only very few were actually able to have gotten a taste and known the joys of being able to experience the ultimate blood of ecstasy. Because it was not something anyone can just have.
There was a consequence if a vampire drinks a light fae's blood and it was not a simple one. Upon the consumption of a light faes blood, it would turn into a type of poison in that vampire.
