Zelios' Book Fragment
…Svarog, Byelobog and chief among them, the demon-god Kupala, whose offspring infuse the very soil with madness. His dark heart ripped asunder, the demon is said to rest beneath the Carpathians, haunting the lands and spreading his corruption to all who touch upon his dread demesne. It is whispered that the demon sleeps, gaining strength to rise in terrible wrath when at last he awakens. His burning malice is seen in the creation of a legendary blood-red bloom known as the sacred fire-flower of Kupala. With it, sorcerers may bind or loose demons.
The cult dedicated to this abhorrent spirit gifts the demon with sacrifices, slaying babes for their pure and innocent blood, which the demon consumes. Thus fortified, Kupala’s corruption spreads ever farther, trailing lunacy in its wake. The quaking of the earth, the foul rains and lightnings that destroy crops and homes, great windstorms that tear the fields and forests asunder, all these speak with the demon’s voice. May God grant that we discover…