A/N - I do not own any of the characters or universes used here...I just like playing with them and will return them unharmed when I get bored or the plot bunnies abandon me for greener pastures.
Long ago a space-faring race called the Goa’uld came to Earth in search of conquests. Before long they had set themselves up as Gods and Goddesses of several pantheons, but most especially Egyptian. They adopted the names of the local deities and collected worshippers and slaves alike.
This ticked off the real Gods and Goddesses.
The deities fought back in various ways based on what their particular area of specialization was. Unfortunately, gods only have the power that humans had endowed them with and this was before the rise of the One God who was omnipotent and omniscient; their magic was not quite a match for the Goa’uld’s technology.
One Goddess, Bastet, who had been originally created as a goddess of war and had gradually changed into a goddess of cats, fought Her own war against the imposters by granting a portion of Her divine powers to one of Her priestesses. She would give the woman strengths and abilities proportionate to the felines that She governed and would set her against the enemy. If she fell, then Bastet directed the power to another champion while gathering the soul of the fallen and cherishing it.
This worked fairly well for about a century, until the Goa’uld realized that as soon as they would kill one thorn in their side another would appear shortly thereafter and continue needling them. Eventually the Goa’uld who had assumed the name of Ra managed to capture the most recent of Bastet’s cat women and imprisoned her in one of his regenerating sarcophaguses; which he then placed in storage aboard his mothership.
This stopped the attacks, and before Bastet came up with another tactic the human rebellion that drove the Goa’uld off the planet occurred. Ra forgot about the prisoner he had collected in the haste to leave and she was relegated to routine maintenance in a mostly unused portion of his vessel.
Bastet did not reclaim Her power from Her priestess as that would break the vow that She had given upon granting it initially; and so the priestess slept, unaging, in the darkness of space over the next several millennia while the humans of Earth learned their own technology and gradually forgot the worship of the old deities which caused those same deities to diminish in power and fade away. Unfortunately, unlike deities, demons were not dependent upon belief to exist and they continued to thrive.
Most likely the priestess would be asleep still, except that one Colonel Jack O’Neill and one Dr. Daniel Jackson managed to transport a hydrogen bomb aboard Ra’s ship before it exploded; destroying Ra, his mothership, and everyone on board…including one divinely-touched priestess, which released the power of Bastet to be sent to the next priestess.
The power hesitated, with Bastet no longer being worshipped there were of course no priestesses; and the Goddess Herself was diminished enough to be barely aware as the power sought a new home, although the brush of Her own power did begin to rouse Her. With no other direction, the power followed the blood-line of its last host and sought a surviving, female descendant. Eventually it found one in Sunnydale, California – a Miss Cordelia Chase, senior in Sunnydale High School.