The Crystal Sphere was worn by Melbu Frahma, and it contained the God of Destruction's power. He harnessed the sphere's energies to give himself unlimited magical power, so that he and the Winglies could rule over all the other species. This was fuel for the humans' uprising and thus eventually began the Dragon Campaign, a war for equality, prosperity, and freedom.
In fact, the Crystal held not only the power, but the soul of God of Destruction, separating it from the body to prevent the birth of the 108th Fruit, which was created by Soa, the creator, for no other purpose than to destroy. The soul kept by Melbu Frahma, the body sealed away as The Moon That Never Sets. Winglies, the 107th species, kept the 108th from being born and used its power to dominate all other species.
However, the Crystal has been destroyed by none other than the Red Dragoon Zieg, in his fateful duel against Melbu Frahma. Release from its prison, the soul of the God of Destruction was born into the being known as the Moon Child every 108 years, in an attempt to reach its body.