Disclaimer: this is a work of a fan for fans and is not made for profit. I do not own Aria (well I have the first season anime boxset and the first two Aqua manga but not the rights) which is the property of Kozue Amano and licensed to others but not to me (more the pity). Please enjoy and (begs) don't sue!
Epilogue
Years, decades and even centuries flew by and he would find out her pure gentle soul was rarely reborn. He changed over time and stayed in his large bakeneko form and traveled earning names from the humans. Yet he would hear in the wind of time of a girl born sweet, kind and gentle with wonder of the world in her eyes and he would return to find her and watch over her once more. After all, she was his undying love.
Still between those times, he learned more of things and became more than just a monster cat. He found a duty reminiscent of her love and became a king of cats. He took care of them as needed much as she once had for him and they responded with the same respect for him as he had to her. When humans chose to find their way to the stars, they took his subjects with him and he followed to complete his duty. Still he had not forgotten his promise and when he read the winds, they told him while she would be reborn upon the old earth, she would find a new happy home on a different world. He settled there to wait for her arrival.
Akari Muzunashi had arrived to Aqua from Manhome and she knew with a joyful feeling she was home. She was determined to do her best to become an undine and nothing would stop her. Her eyes filled with joy for everything, the kind and gentle girl somehow found her way into everyone's heart. Still, she possessed an uncommon soul that often found its way to odd adventures. One such adventure had her meet the King of Cats. Cait Sith saw her and knew she had finally arrive. He was happy to again fulfill his promise to her once more.
"No matter when you are reborn, I will love and protect you always."