Y's II: Castle in the Heavens (1992)

Adol Christin is taken to the flying land of Ys after defeating Fact and uniting the six books of Ys. He is taken and cared for by Lilia, a red haired girl from Rance Village. Adol learns quickly that the people on this land believe there is nothing beyond the barriers of their land, and that the monsters are the Gods who created the land. Adol challenges their beliefs and through strong opposition, proves himself right, but soon after he has to save the people from the truth...and face the darker side of himself.