Which artifact, known as an Apple, is central to the Assassin's Creed series?

The Apple of Eden is the artifact central to many Assassin's Creed stories.

It is one of the Pieces of Eden, fictional ancient devices created by the Isu, an advanced civilization that existed before humanity's recorded history. The Apples are depicted as powerful spherical artifacts capable of influencing minds and producing other extraordinary effects.

The first Assassin's Creed game places an Apple of Eden at the center of Altaïr's conflict with the Templars. Later games reveal that different Apples exist and that their history is connected to the Isu and the origins of the human-Templar conflict.

Players sometimes use “Apple of Eden” as if it were the name of every Piece of Eden. That is not correct: other artifacts include the Swords, Staves, Shrouds, and the Trident of Eden. “Apple” identifies one particular type within the broader group.