Gleipnir

Gleipnir (グレイプニル) is a set of spiritual items, crafted by Ellasone and based off the dwarven-forged chain which was used to bind Fenrir until Ragnarok in Norse mythology, which are used to protect St. Julian's Cathedral.

Etymology
Gleipnir (Old Norse "open one") is the fetter which is used to bind the wolf Fenrir until Ragnarök. Commissioned by the gods after two previous chains failed to bind the wolf, it was forged the dwarves using six supposedly impossible materials; the sound of a cat's footfall, the beard of a woman, the roots of a mountain, the sinews of a bear, the breath of a fish and the spittle of a bird. Though thin as a silk ribbon, it was stronger than any iron chain and virtually impossible to break.

Principles
Gleipnir is a set of over thirty autonomous spiritual items, which react to intruders and intercept them. They are made out of magically manufactured steel and crafted into a number of giant animal-related shapes, including snakes, octopuses and bats. The metal snakes are over 15cm thick and over 5m long, capable of crushing marble pillars when wrapped around them.