In the Assassin's Creed series, the fictional precursor species that created the Pieces of Eden is called the Isu.
The Isu are an advanced civilization that existed before recorded human history in the series' universe. They created humans and developed powerful artifacts, including the Apple of Eden, the Staff of Eden, and other Pieces of Eden. Their technology is later mistaken for magic or divine power by human societies.
The Isu were once commonly described in the games as the “First Civilization.” That phrase is a description of their place in history, not their species name. The term “Those Who Came Before” is another title used in the series, which can make terminology confusing.
Many major Assassin's Creed stories connect present-day characters to Isu figures and memories. Despite their enormous influence, the Isu are not the same as the human Templars or the modern corporation Abstergo.