The Apple of Eden is the precursor artifact that often grants visions in Assassin's Creed.
Apples of Eden are Pieces of Eden, advanced artifacts created by the Isu, the precursor civilization in the series' mythology. They can influence minds, create illusions and reveal visions, making them powerful objects sought by both Assassins and Templars.
The Apple is not a single unique object in every storyline; multiple Apples exist, and different games show different users and effects. Other Pieces of Eden include swords, staffs and shrouds, so the artifacts are easy to confuse. The name deliberately echoes the biblical apple, but the series treats it as fictional Isu technology rather than a religious relic.