According to Assassin's Creed lore, the precursor civilization 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' fictional universe. They created powerful artifacts known collectively as Pieces of Eden, including the Apple of Eden and the Staff of Eden. These objects can influence human perception, control behavior, or produce other extraordinary effects.
Earlier games often referred to the Isu as the First Civilization or Those Who Came Before. Those expressions describe the same broad precursor culture, while Isu is the name most commonly used in later lore and reference material. The Isu are also connected to the creation and enslavement of humanity, as well as the catastrophe that devastated their world.
The Isu should not be confused with the Templars or the Assassins. Those are human organizations that seek different goals and sometimes fight over Isu artifacts. The Order of the Ancients is another historical precursor to the Templars, not the civilization that originally made the Pieces of Eden.