- This article is about the object. For the book, see The Subtle Knife.
The subtle knife, also known as Æsahættr or teleutaia makhaira was a knife with a blade so fine it could rip through the fabric between the worlds of the multiverse.
Appearance and Abilities
A knife with a double-edge, the subtle knife possessed one edge of keen steel, which could cut through any physical material. The other edge was even sharper, extending to a point so fine that the eye could not see it. This edge was able to search out gaps in the fabric of space and thus cut through the fabric of the universe and into alternative universes. No known material was able to resist the knife, although it was breakable, should a wielder attempt to use it whilst thinking about a person they loved. It was the belief of certain individuals that this was because the knife was incapable of cutting through love.
The knife was made by philosophers of Cittágazze, from the Torre degli Angeli, who cut many windows in their world. The full list of its bearers is unknown, but the first bearer known by name is Giacomo Paridisi, who won it in a fight with the previous bearer, and lost the two small fingers on his left hand obtaining it. He hid in the Torre degli Angeli from the insurgence of Spectres in his world, for many years protecting the knife. A young Cittágazze man named Tullio tried to take it from him, but Lyra Silvertongue had been sent by Carlo Boreal to take the knife, and her new-found friend and companion Will Parry fought Tullio, prevailing, obtaining the knife, and losing the same two fingers in the process — marking him as the new bearer.
Lord Boreal and the Magisterium of the Church wanted to possess the knife because its ability to cut through any material threatened their Authority, who had survived the First Rebellion only because the rebel angels could not harm him with any existing weapon or material at the time (their fears were later confirmed when Will and Lyra used the knife to free the Authority).
Will and Lyra instead took the knife and used it to travel between their worlds for a long while, though the knife once broke when Will, trying to open a window, was distracted by the thought of his mother. The shattered pieces were collected by the two children, though, and repaired by the armoured bear and great metalworker Iorek Byrnison.
Iorek warned Will and Lyra that the knife had purposes of its own — indicating an intelligence akin to that of the alethiometer. He also indicated these purposes might not be good. Later, the angel Xaphania explained that Dust had been leaking out of the worlds through the windows made by the knife, and that, each time the knife made a window, it drew up a Spectre from the Abyss. Thus all windows leading between worlds had to be closed by the angels, except for one. Will and Lyra initially believed this one window could be between their worlds, but then realized that they had made a promise to the shades in the world of the dead: to leave them an opening so that they can leave it and rejoin the universe, by emerging into the world of the mulefa. Thus, Will realized he had to shatter the knife. As people in the multiverse are not capable of surviving for long outside their own universes, it was also necessary that Will and Lyra each return to their own worlds.
- Æsahættr literally means "God-Destroyer".
- Teleutaia makhaira means "the last knife of all".
Behind the scenes
- It is possible that the knife may have been inspired by Saint Michael's sword in Paradise Lost, which was specially designed by God to cut through even the substance of angels.