The Diamond Keys

This is my Third Story (my poems don't count)
hope you like it!

One night a girl came across an rectangular box with gold lining and in the center of the box is a title but is covered by a note.
"Dear Kiyomi, if your reading this then you must have found the box. I want you to take care of these keys until you have found a suitable Celestial Spirit Mage."
p.s. "you can use these keys when you are in trouble. There is a note inside to tell you how to use them."

Love,
Acnolagia and SunnySea

Read and find out what all of this means!