Gwendolyn's Echo was a guild consisting of five peculiar mages. These mages suffer Occult Amnesic Syndrome, a deficit in memory caused by Ethernano. These five mages had forgotten their past and where they came from. Through years of research, the five mages have found out that there is one cure to their Amnesia. They found out that a mage as pure as snow is able to cure any magic-related disables. Her name was Gwendolyn Gloombrace. In time, more and more mages join the guild, which led the five founding mages to create their own guilds and abandoning previous mission of searching for Gwendolyn Gloombrace. These five guilds are soon known as the Echo Alliance.
The Grand Magic Games is an annual event which determines the strongest guild in Fiore. Hyacinths of the Heavens, a guild which is based in Sycamore Town and a member of the Echo Alliance, finds its way to the Games. Soon, they are confronted by the Master of their sister guild, Myllbank Santoro of the Mortal Knights guild. Ever since, he is obsessed with hunting down the pure mage, Gwendolyn.
In the epic conclusion to the Devil's Deal series, Freya has one final chance to discover the full potential of her own power, and to use it to restore balance in the universe - once and for all. After the destruction caused by Roisin, Ferya and Torix come to terms with their losses and mistakes... And prepare for a final battle that will change everything.