Black Bullet (Projectile)

Black Bullet is a projectile created from Varanium, which can harm Gastrea.

Description
With their gun, the user's main projectiles of choice are Black Bullets, which are created from the very same object that keeps Gastrea away from the Monoliths, Varanium. It has been stated that with said bullets, Gastrea will not be able to recover; giving the user the upper hand when in combat. These bullets were able to harm a Gastrea Stage I greatly, in contrast to when Tadashima attacked with regular bullets to no effect.