After completing over Standard difficulty with S rank, you will get it in item box.
Its performance is normal. But, it has ∞ ammo. Although stats of Samurai Edge is lower than other ∞ weapons, it is helpful to downgrade tension thanks to ∞ ammo.
In Extra Modes, Robert Kendo has this with not ∞ ammo. It is used vs poison zombies on mid-long range.
