Disclaimer: I do not own Sailor Moon or Final Fantasy X.
Prologue
Decades have passed since the ascension of Tsukino Usagi into Sailor Cosmos. Now, at long last, Chaos has been destroyed. However, its destruction has come with a price. Sailor Cosmos has been gravely injured, and floats now through the emptiness of space, minutes away from death. Moments before her final breath, Cosmos made one final wish upon the Ginzoushou. That wish was that she be released from her duties as Sailor Cosmos and Princess/Neo-Queen Serenity, and that she be reborn to the world of her true soul-mate, where the fate of the world would not rest on her shoulders. Then she took her last breath, and the Ginzoushou encased her body within itself before exploding into millions of tiny diamonds that then proceeded to scatter across the barren universe, bringing new life to the planets through her essence.
Mere moments later, in a completely separate dimension, a baby girl was born. She was absolutely gorgeous, with her mop of curly silvery-blond hair and her large ice-blue eyes. The baby let loose a mighty wail, and her exhausted, dying mother smiled softly before closing her eyes for the last time, the last word to leave her lips being her baby's name, Kelinda. Meanwhile, as the midwife bathed and swaddled the newborn baby girl, her father, the Summoner Braska, paced outside in the waiting room, his wife and eight-month-old daughter, Yuna, sitting nearby. How can his wife be in the waiting room with him when a woman had just given birth to his child, you ask? Very simple.
Kelinda's mother had been a young Summoner from Kilika whose father had arranged a marriage with Braska, through his father, shortly after her birth and his third birthday. As she grew, Kelinda's mother fell in love with Braska, only to have her heart broken when he chose to, instead of marrying her, elope with the Al Bhed woman who was now his wife and the mother of his firstborn daughter, Yuna. Three years passed and news of Yuna's mother's pregnancy reached her ears. This infuriated her, and so she began concocting a plan to seduce Braska. She succeeded, but only through use of potions and powerful magic, and the result was her pregnancy. As he had with his wife, Braska provided for her during her pregnancy, though it was not enough to draw him away from the arms of the woman he loved.
Kelinda, now clean and wrapped in a soft pink blanket, was soon brought into the waiting room and placed in her father's arms even as he was informed that her mother hadn't made it. Braska brought her home to be raised by Yuna's mother, and life moved on. It soon became apparent that young Yuna would follow in her father's footsteps and become a Summoner, as she could often be seen playing with her father's summon, Valefor. Only Braska seemed to notice his youngest daughter's potential, often catching her either humming or singing the Hymns of the Fayths of various temples, despite never having been privy to the Chamber of the Fayth.
Yuna and Kelinda became apprentices at the same time, six years after Yuna's mother's death when they were four. Yuna struggled in her studies, whereas Kelinda excelled. However, it was well known that Kelinda was the bastard child, and so she was given no praise, only scorn. The only ones that seemed to truly care for her were Lulu, Kimahri, and Wakka, the Guardians she shared with Yuna. Braska defeated Sin when the girls were six, bringing about the Calm. Now, eleven years later, Sin had returned, and Yuna had just turned seventeen, Kelinda still being sixteen. Today was the day that the girls would enter the Chamber of the Fayth and pray to receive Valefor.
With Lulu and Kimahri's help, Kelinda and Yuna navigated their way through the Cloister of Trials. When they reached the Outer Chamber, their Guardians wished them good luck and the two girls entered the Inner Chamber on their own. Immediately Yuna kneeled at least two yards from the altar and fell into deep meditation. Her lips moved in Silent Prayer, the method used by Summoners for centuries to attain their Aeons, and the world ceased to exist to her. Meanwhile Kelinda's eyes fogged over as she entered into a trance. The Hymn of Valefor's Fayth left her lips in whispered song as her body gently swayed. Soon, though, her voice rose, and her body began to dance gracefully in an intricate pattern of spins and jumps.
After only an hour of this, the translucent spirit of Valefor appeared floating above her altar, visible only to Kelinda, and her voice quieted and her body slowed its movements to a halt. Eyes locked and a silent conversation ensued, ending with Valefor blessing Kelinda with her power. Several hours later, Yuna was also blessed. Kelinda helped up her exhausted sister, and together they made their way through the narrow tunnel at the end of which lay the door to the Outer Chamber. The door opened, and Yuna stepped out. This is where the true story begins.