|Spoiler Alert: This page contains spoilers. Read at your own risk.|
Invisible Bullet (不可視 弾丸) is a Weight Type Magic that is Kichijouji Shinkurou's trump card. Since it relies on a Cardinal Code, this Magic has no need to define the altered phenomenon that is mandatory in normal Magic because the driving force itself has been defined. Under this condition, 'Invisible Bullet' has no need to rewrite the surface that force was applied on regardless of whether it was a wall, the surface, or even the human body. 'Invisible Bullet' is a magic that directly improves the force itself.
Not rewriting the entire Eidos, the Magic Sequence needs to rewrite only the necessary portion is naturally going to be smaller. Because this is not altering the Eidos of the target itself, 'Data Fortification' — abilities that defend against rewriting the Eidos — is unable to defend against it.
A smaller Magic Sequence and the ability to influence the Eidos in spite of Data Fortification gives the user a powerful advantage over an opponent for using this type of magic.
However, 'Invisible Bullet' is hampered by the absolute necessity of visual confirmation. Rather than relying on the Eidos, a direct confirmation of the object is a necessary, but ironic, handicap. Owing to this handicap, cover is a useful defense against the attacks from 'Invisible Bullet'.