Aeons?

I am known throughout Spira by all but one; - Tidus
In the face of defeat and sorrow, I bring hope; - The Aeons are thought to be the only way to defeat Sin
Bestowed with valor, strong you will become. - The bless the summoner, and Yuna's faith is what makes her strong.
The song of songs, my reprise is a kaleidoscope - Hymn of the Fayth, and when an Aeon dies...
of the peace and prosperity of the rising sun. - the pyreflies look like a kaleidoscope held up to the sun.