Introduction
"The history of the nations is most often told through the deeds of the Avatar, and little is known of the time before the Avatar Cycle began. Master of the four elements, each Avatar bore a responsibility to maintain balance in the world- but the Avatar did not fight alone. A close examination of scrolls housed in Wan Shi Tong's Library reveals a fascinating phenomenon; a hidden history, revolving around one woman – the Vampire Slayer. The prophecy of the Slayer reads as follows:
"Into every generation a slayer is born: one girl in all the world, a chosen one. She alone will wield the strength and skill to fight the vampires, demons, and the forces of darkness; to stop the spread of their evil and the swell of their number. She is the Slayer."
It is therefore clear that these Slayers are called forth when they are needed, and when one Slayer dies, another is chosen– much like the Avatar, in the need for cyclical continuation, and yet unlike it, since there is no pattern, no way of knowing which girls will be chosen. These Slayers have been in existence for hundreds of years, and seem to have been born at the same time as the first Avatars.
The scrolls are not bound in any chronological order, and are based solely on witness testaments, but it appears as though an Avatar has worked closely with a Slayer on multiple occasions, when the Slayer did not work alone, in secrecy as the situation demanded, although many Avatars seem ignorant of the existence of Slayers, perhaps taking it to be no more than a vigilante woman.
Despite being a physical being, the Slayer seems to have been created in order to further balance the scales of good and evil in this world, and serves as a weapon for the spirit world, being tasked with countering evil spirits that walk the land, the aforementioned vampires, demons and miscellanea demons that by all accounts would otherwise overwhelm the world.
Recent testimonies seem to indicate that one such Slayer battled alongside the Avatar Aang in his battles against the Firelord Ozai in the final year of the Hundred Years War. The identity of the Slayer in question is believed to be Master Katara of the Southern Water Tribe."
- A Treatise on the Vampire Slayer , by Professor Zei, Former Head of the Anthropology Department at Ba Sing Se University, Assistant Librarian in Wan Shi Tong's Library, the year 157 ASC (After Sozins Comet)
