Fai Hydras

If the monsters of Allaria are born out of the Fai from the dreams of mortals, hydras are a manifestation of unbridled nightmares. Dating from the most primal age of Valerna, hydras are terrifying, unnatural creatures of enormous size, improbable anatomy, and insatiable appetite.
A hulking reptilian creature with many heads— ranging from five to a dozen, or even more—atop just as many long, serpentine necks, a hydra is all but indestructible. Only by destroying all of its heads can a hydra be felled—a gargantuan task, for to battle such a beast is akin to fighting a dozen monsters at once.
Legends tell that the realm of Allaria was founded by the blood of a Fai hydra, when the human huntress, Karra, and the elf king, Arn Zai, united to battle the most powerful hydra ever seen. The thirteen-headed abomination threatened to lay waste to the land, and Zai decreed that whichever of them could claim the most heads would rule the city of Taessai. In a lengthy battle, the two heroes claimed six heads apiece, and took the thirteenth together. In that moment, Zai saw a worthy bride in Karra and proclaimed his devotion. The first elf– human marriage took place, and from their union the first honor elves were born.