Red XIII, is truly Nanaki, who's home is at Cosmo Canyon. He joined Cloud to teach himself what's right and grow up to be a great warrior like his father, who risked his life to protect everyone when there was once a war at Cosmo. All that was left of him was a statue.
P.S. LOOKS LIKE A SAD STORY, HUH? WAIT UNTIL YOU SEE ARIES.
