Ideal Closer

Corundum Magic: Ideal Closer (鋼玉魔法『』) is a Corundum Magic spell.

Description
With an open grimoire, the user's body is completely covered by corundum with only a Y-shaped opening for their eyes and mouth. The armor takes a larger humanoid shape, complete with arms and legs. The user is able to control the armor and use the limbs to attack a target.