Board Thread:General Discussion/@comment-27741659-20160206144154/@comment-679780-20160211210150

What I liked about Sonic Unleashed was that it expanded on the world of Sonic. (Literally), we learned that Sonic's world is different from ours but still regarded as "Earth" and has cultures similar to ours. We also learned about a culture that predates the 4000 year old Echidna tribes for over tens of thousands years, this culture creating the Gaia Temples.

This prooves that the Chaos Emeralds are not of Echidna origin and been around, possibly since the birth of the planet given there importance in the Times of Awakening. However it could be possible the Echidna's found the emeralds as well as the God of Destruction guarding the emeralds and assosiate them with him.

(I have another, weaker theory that Lost World could be the Gaia Temple to the Master Emerald, but I could be wrong.)