Grimoire

Grimoires (グリモア) are a type of magical tome used by Exorcists in combat.

Spells
"O' Sylphs born of the dark mist. Gather in the lands of honey and milk. Spread your crystalline wings and dance in the sky!"

Four exorcists chant the above spell, causing the grimoire to glow purple and rise into the air. Flipping itself open, it unleashes a barrage of golden light, piercing the target multiple times. This attack is strong enough to bring down a large, reptile-like demon.