Sword of Eden #1 was one of the Swords of Eden, sword-like artifacts created by the First Civilization scientist, Hephaestus, to fight during the War of Unification. These Pieces of Eden seemed to grant their bearers great power and leadership, and were later used by influential humans in war and conquest.
By the early 14th century the Sword was in possession of the Knights Templar. After the Templars were branded as heretics in 1307 by Pope Clement V, and the Parisian Temple was attacked by King Philip the Fair's forces, Grand Master Jacques de Molay entrusted his advisor with hiding the Sword. The advisor obliged, concealing the Sword along with de Molay's codex within a secret underground chamber, before being killed by an Assassin.
In 1794, during the French Revolution, the Sword hidden in the Parisian Temple was acquired by François-Thomas Germain, who used the Sword during his fight with Arno Dorian and Élise de la Serre. The Sword granted Germain extraordinary abilities, such as teleportation and deadly energy blasts. Unfortunately, Élise struck a blow to the Sword which destabilized its power source; the subsequent explosion demolished much of the Temple, killed Elise and mortally wounded Germain himself. Following the event, the Sword ended up in Arno's possession, though while it no longer possessed its former powers on account of the damage caused in Élise's final charge, it remained as one of the most powerful weapons in Arno's arsenal.
- The Sword is unique in that it is the only Piece of Eden that can be kept and actively used by the main character after the game ends. The Apples of Eden are sealed away, the Staff disappears and the Shroud is returned to its resting place.