Dawn Summers, sister to the Slayer
was once a mystical energy known
as the key, and hunted down by a
being by the name of Glory.

Created as a Sister for Buffy, to
keep the power of the key safe.

False memories of Dawn being a part
of Buffys life, and to all who knew the
Slayer were planted by the monks who
created Dawn in the hope that the
Key would never be found.