Backbiter is a double-edged sword made of two metals: tempered steel and Celestial Bronze. This means that it can wound or kill mortal, 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. A long sword for one hand, described as being a foot longer than Percy's Riptide. This makes Backbiter 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 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, 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.