- “We cannot give you knowledge. Only power.”
- ―Unidentified Shadowman[src]
In the Primordium Age, the Shadowmen chose a young girl to fight against the forces of evil. They chained Sineya to a cave so that she could not escape, and infused her with the heart, soul, and spirit of a demon. At the cost of most of her humanity, the First Slayer was created.
This made the girl have superhuman strength, speed, reflexes, agility, and healing, so they were able to banish the Old Ones, and continue to fight the threat of demons and vampires. After her death, she would persist into the dreams and visions of her successors.
The Slayer never had a Watcher, and worked in solitude, excluded from the community she saved. However, the descendants of the Shadowmen and their subsequent apprentices would later form the Watchers Council, responsible for identifying, training, and guiding the Slayer, as well as Potential Slayers, giving continuity to the fight against evil.
In 2003, the last guardian of the Hellmouth, Buffy Summers, attempted to communicate with the Shadowmen through a mystical set of shadow casters. They tried to give her more power by repeating the process through which they created the First Slayer eons ago: infusing Buffy with the same demon. However, Buffy rejected it, as she sought knowledge instead of power, and she knew that the cost of her acquiring more power would be her humanity, just as it was for Sineya. The Shadowmen attempted to yield to her determination, but before she was sent back, they gave her a vision of the Turok-Han army led by the First Evil, which led her to think that she may have made a mistake by rejecting the power they offered her.
The Shadowmen were directly responsible not just for the creation of the first Slayer, but also for establishing the line of Slayers, as well as the mystical forces that governed a Slayer's activation. Besides this, their magic also created a great number of Potential Slayers, but only one in each generation would be chosen. However, in 2003, Buffy and Willow altered the rules the Shadowmen established by simultaneously casting the Slayer Activation spell on multiple Potential Slayers to become full Slayers.
- Prologue (Only mentioned)
- Ready, Steady... (Only in flashbacks)
- "Get It Done"
- "End of Days" (Only mentioned)
- "Chosen" (Only mentioned)
- "Damage" (Only mentioned)
- The Reckoning (Only mentioned)