|“||A great blade whose bearers are given the name Zangetsu, or "moon sunderer."||„|
|~ In-game description|
Zangetsuto is a fairly unremarkable-looking katana, with a white-edged silver blade, a simple bronze-colored guard and a black-wrapped grip.
Zangetsuto is Zangetsu's trademark weapon. During their second encounter in the Oriental Sorcery Lab, Zangetsu reveals to Miriam that Zangetsuto is the only weapon that can defeat Gremory, the demon at Gebel's side who is secretly controlling him. However, Gremory knows this as well, and as such has taken great caution in avoiding Zangetsu whenever possible, as he also has the ability to seal Gremory's teleportation. Believing that Miriam has a better shot at defeating Gremory and releasing Gebel from her control, Zangetsu relinquishes his sword to Miriam.
During the boss battle with Gebel, the moon in the background will turn blood red with an aura when Gebel's health is dangerously low. If the moon is struck with Zangetsuto, Gremory will unveil herself and flee, releasing her hold on Gebel in the process; however, this causes his crystallization to instantaneously accelerate, turning him into crystal and killing him soon after.
In pursuit of Gremory, Miriam takes Zangetsuto to the Garden of Silence, where she finds an identical blood-red moon; striking it, she causes Gremory to flee to the Den of Behemoths, leaving behind a portal for Miriam to follow her.
After defeating Bael and sealing the Castle away, Miriam plants the blade of Zangetsuto in the ground, intending it as a memorial to its fallen master: however, after she turns away it is revealed that the sword has disappeared.
As with most items related to progression, Zangetsuto is removed from the player's inventory in New Game Plus and must be re-acquired.
Zangetsuto is a 45 ATK katana that inflicts Slash damage: Miriam cannot duplicate Zangetsu's ability to apply elemental effects to the weapon. It is the third-strongest katana in the game, after Mikazuki and Grand Izayoi. By default it has access to the Techniques "Crescent Stroke" and "Eleventh Hour."
When used against Gremory, Zangetsuto hits twice per swing and all hits are critical.