Arch-Enemy Event Weapon

The Nox Nyctores causality weapons (事象兵器アークエネミー, Jishō Heiki Āku Enemī, Arch Enemy causality weapons) are a set of ten weapons.

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The final stage of Ars Armagus. These armagus were tempered as a set of close range and melee-type weapons to directly oppose the Black Beast. They are also known as "causality weapons". An advanced tempering technique was needed to forge them, and a total of ten weapons were planned.

The first nine were created during the First War of Magic, based on the Sankishin, to combat the Black Beast. Only those with the highest proficiency in the "Proper Use of Ars Magus" can wield them, and even then, there is a significant risk of mental burden on the user. It's said that the Nox choose their masters. One of the primary functions of Nox Nyctores is to unburden their owners of "needless" emotions and enhance others; this has a profound effect, for example eliminating fear, but owners may also find themselves losing their compassion, remorse, etc.

Among the Nox Nyctores, the Murakumo Unit is unique in that it was produced after the Dark War, and is actually an Anti-Sankishin Core Unit, created in a Cauldron as a means to make contact with the Boundary, where its soul exists. During the Ikaruga Federation's 12th attempt to produce one, together with a Sector Seven research team, the experiment was interrupted by an attack from the NOL's Nox: Gigant: Take-Mikazuchi and this resulted in the creation of Noel, in an incomplete state. Afterwards, three base bodies were stolen from the NOL and Nu was created in Kagutsuchi. Ragna's already destroyed the two others.

There are also imitation Nox Nyctores called artificial causality weapons. They rely on atomic power instead of the life energy used during the forging of the Nox. They are replicas, but have comparable power and are recognized by the Nox Nyctores as being similar. Jubei once experienced a resonance created by his Musashi when it came into contact with one. There is an upgraded version of the artificial causality weapon known as an "Idea Engine", but nothing else is known of it. There are a handful of other things that can stand up against Nox Nyctores.