Ex Voto

Ex Voto (エクス＝ヴォト) is a magic method which uses patron Saints and religious icons as intermediates when asking the Son of God for miracles.

Principles
Ex Voto is a method of using patron Saints and religious icons as intermediates when asking the Son of God for miracles. Supposedly when the prayer was completed, an offering to the altar of the proxy was given. The offering used would usually be an object, but Caliche I. Niknosh (and Russian magicians in general) used parchment in which the contents of the prayer was written. Lessar used this distinction against her opponent as she read the parchment and formulated a counterspell to it.

The Agnese Forces have nuns skilled in the use of Divine Mother-style Ex Voto to build shelters. The shelters look like tent-like objects, made of a wooden framework and a large white cloth. They are still not objects that could be constructed in a dozen or so seconds, but the shelters automatically expand on their own using magic. The shelters use the theory of the swaddling clothes and manger of the Son of God.

World War III
When Telesma arms started appearing around the world, causing chaos and panic, Agnese Sanctis instructed Angelene to gather sisters skilled in the use of Divine Mother-style Ex Voto to build shelters to protect Russian and Academy City's soldiers in the plains of Russia, as there wasn't enough time to get them all out from the range of the explosion.

Toaru Kagaku no Railgun SS2: Shopping Mall Demonstration
Ex Voto is the style of magic used by Caliche I. Niknosh in her fight with Lessar, along with other members of her cabal.