Kingdom Hearts χ Back Cover

Kingdom Hearts χ Back Cover is a computer-animated film that serves as the tenth installment in the Kingdom Hearts series. It is included in Kingdom Hearts HD 2.8 Final Chapter Prologue and serves as a companion piece to Kingdom Hearts χ.

The story of Kingdom Hearts χ Back Cover focuses on the five Foretellers. The film is non-interactive and rendered in. It also makes use of Kingdom Hearts III's Kingdom Shader.

Story
One hundred years before the events of Kingdom Hearts Birth by Sleep, the world exists as one, during an event known as the Age of Fairy Tales. The Light of the world is protected by seven individuals in Daybreak Town who wield a weapon known as the Keyblade; an unnamed Master, and his six apprentices, Luxu, Ira, Aced, Invi, Ava and Gula. Through his own Gazing Eye embedded on his Keyblade, the Master has foreseen a devastating conflict which will result in the end of the world, and has his apprentices take measures to heal the world when the conflict is over, as the battle itself cannot be avoided. Each apprentice is assigned a specific task, and forms their own Union of Keyblade wielders to maintain balance in the world. The Master himself departs shortly afterwards, and leaves Ira in charge.

One day, however, Ira discovers a Dark Chirithy. As each Keyblade wielder is assigned their own Chirithy, a Spirit Dream Eater, the presence of a Nightmare Chirithy suggests that someone has fallen to the darkness and is a traitor among the apprentices. Insulted by the accusation, Aced storms out of the meeting and begins to suspect Ira himself of being the traitor after it is discovered that this event was not foreseen in any copy of the Master's Book of Prophecies. Aced persuades Gula to form an alliance against Ira, something that was forbidden by the Master, but Invi, who was instructed to keep an eye on the other apprentices, reports to Ira, leading Aced to suspect that she is the traitor. Aced and Invi clash violently, leading Ava and Gula to intervene. In the aftermath, Gula is shown in possession of the lost page, which the Master had personally bestowed to him in secret. Gula tracks a wounded Aced and reveals this information. Infuriated that Gula knew and allowed them to fight, Aced strikes him down, but Ava intervenes and stops him from finishing Gula. Aced wanders through the streets until he is accosted by Ira. The two agree that neither is the traitor, but Ira advises Aced to stand down for the time being, desiring to see the lost page in Gula's possession. He nearly finds Gula, who is being cared for by Ava, but Ava steps in his way, forcing Ira to retreat. Gula regains consciousness and informs Ava of his plan to lure the Master back by summoning Kingdom Hearts, despite the apocalyptic danger it could pose to the world.

Aware that a conflict within the Unions is now inevitable, Ava fulfills her mission from the Master and gathers as many Keyblade wielders as possible, instructing them to flee into hiding when the Keyblade War erupts instead of fighting and perishing, dubbing them as her "Dandelions". Meanwhile, in a barren wasteland, Luxu is shown traveling with the Master's Keyblade and a mysterious box; the Master bestowed his Keyblade to Luxu, along with the box, which he instructed him never to open, and sent him to journey afar and observe his fellow apprentices with the Keyblade's Gazing Eye. Luxu muses his Master's saying, "May my heart be my guiding key".