Gleipnir

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

Principles
Gleipnir is an autonomous spiritual item which reacts to intruders and intercepts them. It is made out of magically manufactured steel and crafted into a number of giant animal-related shapes, including snakes, octopuses and bats.