Guarding Blade

One of the so-called Nine Shadows, this Tarot ability is extremely dangerous to face, despite it being defensive in nature. Unlike normal Summoned Blades, the Guarding Blade is near-invisible, making it hard to defend against. The untrained eye will simply see flashes as the sword cuts, needing good reflexes to respond and survive.
The Guarding Blade requires intensive control by its wielder. As they swing their own arm, as if wielding a blade, the Guarding Blade will be swung at the place they focus on. By rapidly shifting focus, the wielder can quickly attack various locations. Furthermore, by being located further back, the wielder is harder to attack from a blind spot. This makes the Guarding Blade extremely useful for bodyguards.
Blocking the Guarding Blade is possible, but its control only goes in one direction, as such a block will not imbalance the wielder. The wielder can continue attacking with it, without risking the blade breaking. Even Sealstone solely blocks the blade. This too is different from Summoned Blades, and why the few people capable of this feat are greatly feared and respected.