Kronos' Scythe

Kronos' Scythe is a powerful scythe. It was given to Kronos by Gaia. It was originally wielded by Luke as a Sword known as Backbiter, a sword made of steel and Celestial Bronze.

The Lightning Thief
Luke was first seen using it in The Lightning Thief, using it in the Sword Fighting Arena. Luke used the sword to rip a portal and vanish.

The Sea of Monsters
Luke used the sword again in The Sea of Monsters. He used it on the Princess Andromeda to fight Percy.

The Titan's Curse
In The Titan's Curse, Luke used the sword to fight Thalia.

The Battle of the Labyrinth
In The Battle of The Labyrinth, Luke did not have his sword, as it was being reforged back into a scythe by the Telekhines that work for Kronos.

The Last Olympian
In The Last Olympian, Kronos is seen using his scythe many times throughout the book. In his final fight with Percy, Kronos turns his scythe back into Backbiter because Percy challenged him to a sword fight. With the destruction of Kronos, it's reduced to a pool of molten metal.

Abilities
The Scythe is an extremely powerful weapon. One hit can release lots of energy into a person, severing their soul from their body. Because of its half steel, half celestial bronze blade, it can harm mortals and non-mortals.

Owners

 * Luke (In The Lightning Thief, The Sea of Monsters, The Titans Curse, The Battle of The Labyrinth, The Last Olympian)
 * Kronos (In The Battle of The Labyrinth, The Last Olympian)