The Spellcaster (スペルキャスター Superukyasutā?) are objects or converter units that releases the power of the Lapis Philosophorum and reforms it into an equippable Faust Robe. It has been specially tuned for use with each alchemist. After it converts the light of the Lapis into a Faust Robe, this device acts just like the Symphogear's Armed Gear - as a weapon that is tuned to the user's battle style.
In AXZ Episode 12, it was left behind after the Alchemists brought light upon death to prevent the damage from the missile. As their perfect bodies disintegrated into the sky, the Spellcaster should have vanished along with them. However the force of their will - their bonds, which surpass even perfection, assured that it stayed in this world for just a little while longer.
Saint-Germain's spellcaster has the ability to fire different kind of bullets. In AXZ Episode 12, with help of a special bullet transmuted by Prelati, she is able to complete destroy a nuclear missile. In AXZ Episode 13, Adam Weishaupt used its manifestion energy against Hibiki Tachibana. It appears as a gun.
Cagliostro's spellcaster has the ability to fire a barrage of light-blue energy at her opponents. She is able to create water walls as a defense. She is also able to deliver strong punches. In its unactivated form, it appears as a ring.