The Apple of Eden is the powerful Isu artifact central to many Assassin's Creed stories.
Apples of Eden are Pieces of Eden, advanced artifacts created by the Isu, the precursor civilization that existed before humanity's recorded history. In the games, an Apple can influence minds, create illusions, and produce other effects that later cultures interpret as magic or divine power.
The artifacts are important to both sides of the series' central conflict. Templars generally seek Pieces of Eden to impose order through control, while Assassins oppose that use of coercive power. Several historical characters possess or pursue an Apple, including Rodrigo Borgia in Assassin's Creed II.
The term is singular in a particular artifact's name but also describes a class of related objects. That is why “Apple of Eden” is more precise than simply saying Eden or Piece of Eden, which can refer to different artifacts such as swords, staffs, or shrouds.