Well, welcome to Chocoimo's room for a change. The way it works is that only a strong chocobo, the strongest, will be accepted by the Ciel monolith and then can become the Legendary Ciel chocobo. At least, that's the rumor.
The Legendary Ciel is a legendary chocobo from Final Fantasy: Unlimited. According to legend, it was an armored, flying chocobo with great power. During the course of the series, Yu's chocobo, Chobi, unlocks his hidden power at the Ciel ruins, becoming the Legendary Ciel to help his friends when they are in trouble.
- The theme "Legendary Ciel" is played when Chobi transforms into the Ciel chocobo. This is Track 19 on the album Final Fantasy: Unlimited - Music Adventure Verse 2.