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Backbiter is Luke Castellan's sword which, in The Battle of the Labyrinth, is revealed to be a modified version of Kronos' Scythe.

Luke with Backbiter sheathed.


Kronos with his scythe, the original form of Backbiter.

Backbiter is a double-edged sword made of two metals: tempered steel and Celestial Bronze. This means that it can wound or kill mortals, demigods, and immortals alike and sever their souls, which makes it similar to Stygian Iron. Apparently, Backbiter is also capable of "slashing" open portals, as seen in the final scene in which Luke and Percy meet in The Lightning Thief. It is a long sword for one hand, as it is described as being a foot longer than Percy's Riptide, or four feet long.

In The Battle of the Labyrinth, Backbiter is broken down and reforged by Telekhines in the forge in Mount Saint Helens. Kronos' scythe has the same bronze-and-gray glint as Backbiter, but it is a much larger weapon, with a six-foot-long blade curved like a crescent moon, but is also thin for its length. Adding in the length of the handle, the scythe is a large, long weapon which generally requires two hands to use. Kronos is extremely proficient with it, and he has a nuanced fighting style taking advantage of the scythe's quirks, such as its curved blade and long reach, but also showing skill in using it in its original form.


Backbiter, in its sword form, is used predominantly for close-range warfare and hand-to-hand combat. It weighs probably as much as like Riptide, and can be wielded in one hand along with a shield for the purpose of versality. However, it is used primarily and is more effective when used with both hands. Because it is made of Celestial Bronze and tempered steel, it is capable of physically harming mortals and monsters alike, making it very dangerous. Because it is, in actuality, the weapon of the Titan Kronos, Backbiter is extremely powerful, as when Luke uses it to battle Thalia at Mount Othrys, the clash of both their weapons - in Thalia's case, Aegis - creates an explosion of vicious energy.


Backbiter, Luke called it. An appropriate name. Now that it is reforged completely, it shall indeed bite back.

–Kronos, after he was first resurrected in The Battle of the Labyrinth.

The name Backbiter was chosen by Luke who said it can hurt both mortals and immortals, and can fatally wound a demigod. It is possible that Luke named it this from the phrase "stabbed in the back." When the sword was reforged into the shape of a scythe, Kronos claims that the sword will bite back at the Olympian gods.


  • It is stated to be the only sword that Percy Jackson is afraid of.
  • In The Sea of Monsters, Percy Jackson feels that Backbiter's creation was tragic. He could feel that someone died while it was being forged.
Personal Weapons: Riptide | Annabeth's Knife | Backbiter | Frank's Spear | Hazel's Spatha | Katoptris | Nico's Sword | Thalia's Spear | Aegis | Hades' Sword | Kronos' Scythe | Ivlivs | Master Bolt | Poseidon's Trident | Reyna's Spear | Silver Bow | Hades' Staff | Juno's Gladius | Annabeth's Sword | Sumarbrander | Gungnir | Gjallar | Mjolnir | Thor's Staff | Khopesh | Mallory's Serrated Knives | Meg's Twin Imperial Gold siccae blades | Caduceus | Apollo's Golden Bow | Artemis' Knives | Ares' Sword | Ares' Shield | Thyrsus | Hecate's Torches | Minotaur's Axe | Leroy's Sword | Tyson's Javelin | Alex's Garrote Wire | Piper's Sword
Magical Items: Annabeth's Yankees Cap | Helm of Darkness | Keys of Hades | Flying Chariot | Golden Apple | Apples of Immortality | Greek Fire | Hermes' Multivitamins | Leo's Magical Toolbelt | Nectar and Ambrosia | Pandora's Pithos | Winged Shoes | Golden Fleece | Stygian Ice Whistle | Serapis' Staff | Magic 8 Ball | Arrow of Dodona | Pig Ball | Mechanical Spider | Angel Statues | Athena Parthenos | Chiron's Wheelchair | Diocletian's Scepter | Flaming Dodgeball | Gleipnir | Poseidon's Pearls | Queen Hippolyta's Belt | Mistletoe Arrow | Frank's Stick | Expand-o-Duck | Caligula's Caligae | Ran’s Net | Rune Stones | Nábrók
Spoils of War: Minotaur's Horn | Medusa's Head | Kampê's Scimitars | Nemean Lion's Pelt | Gorgon Blood | Cornucopia | Lydian Drakon Hide | Phineas' Robe and Slippers | Triptolemus's Almanac | Odysseus' Astrolabe
Items: Camp Necklace | Chameleon Armor | Daedalus' Laptop | Golden drachma | Denarius | Red Gold | Mark of Athena | Thalia's Shield | Video Shield | Wristwatch Shield | Golden Mango | Sibylline Books | Letter of Recommendation
Ships Amos' Boat | Argo II | CSS Birmingham | Egyptian Queen | Julia Drusilla Yachts | Pax | Queen Anne's Revenge | Reed Boat | Naglfar
Blessed Metals: Adamantine | Celestial Bronze | Imperial Gold | Stygian Iron | Bone Steel