The Isu are the fictional precursor civilization in Assassin's Creed lore.
The Isu are an advanced civilization that existed before recorded human history in the series. They created many powerful artifacts, including Pieces of Eden, and engineered or controlled early humans before their civilization was destroyed by a catastrophic solar event.
The series gradually reveals Isu history through ruins, holograms, messages, and genetic memories. Figures such as Minerva, Juno, and Jupiter are associated with this civilization and its surviving plans for influencing the human future.
The term is sometimes confused with names used for related groups or historical enemies. The Ancients are an organization in Assassin's Creed Origins, while the First Civilization is another common description of the Isu. Isu is the concise canonical name used throughout later lore.