Arch-Enemy Event Weapon

The Nox Nyctores are a set of ten weapons.

Information
Unlike Ars Magus, these grimoires were intended to be used as armaments from the very start, and were tempered as a set of weapons to 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: Highlander: 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.

No. 01
Owned by the NOL. Its form is that of an attack satellite. The kanji for Highlander is literally "Giant" and is localized as "Gigant". Take-Mikazuchi is a Japanese thunder god and patron saint of warriors. It is commonly mistaken to be The Black Beast itself. According to Continuum Shift, it was sealed away after the war due to fear of its use.
 * Highlander: Take-Mikazuchi

No. 02
Owned by Jin Kisaragi. Its form is that of a Japanese sword. Hyouken is localized as "Mucro Algesco". Yukianesa, "snow woman", is a Japanese fairy. Continuum Shift states its blade is ice, and its power is manipulating the water in the atmosphere.
 * Hyouken: Yukianesa

No. 03
Owned by Noel Vermillion. Its form is that of a pair of handguns. Noel calls them "Demon Guns", localized as "Arcus Diabolus". Bolverk is Odin, disguised in his human form. According to Continuum Shift, it can attack targets through walls, Optic Barrel being a dimensional collapse of sorts at a point in line with the barrel.
 * Majuu: Bolverk

No. 04
Owned by Carl Clover. Its form is that of an automaton. Kishin is localized as "Deus Machina". Nirvana is a transcendent state of enlightenment and tranquility in Buddhism. Ada Clover's body was used in her creation.
 * Kishin: Nirvana

No. 05
Owned by Jubei. Its form is a pair of kodachis, one stored in each end of the sheath. It's apparently named after Musashi Miyamoto, a historical samurai known to fight using two swords in hand. Supposedly its power is to cut 'what cannot normally be cut', what this means is unclear.
 * Mujin: Musashi

No. 06
Owned by Hakumen. Its form is that of a nodachi. Ookami means "Howling God" or "wolf" depending on the reading. It can also mean "Great God" and is a frequent honorific used for Shinto gods. According to Continuum Shift, it is made of a metal that negates Ars Magus in a certain distance, explaining why Arakune can be killed by it in Calamity trigger rather than reform.
 * Zanma: Ookami

No. 07
Owned by Platinum the Trinity. Muchourin means, very roughly, "Untolled Bell". It is localized as Arma Reboare. Its power is altering matter and generating matter.
 * Raigou: Muchourin

No. 08
Owned by Terumi Yuuki. Its form is that of a pair of butterfly knives. Ouroboros is the symbol of a snake eating or biting its own tail. It is believed that this Nox Nyctores can directly attack the mind and psyche of the victim.
 * Jasou: Ouroboros

No. 09
Owned by Bang Shishigami. It is believed to posess the power to destroy other Nox weapons as well as severe ties with the Boundary, but only Platinum knows what happened to it since the war (Bang is unaware of its power).
 * Houyoku: Phoenix Rettenjou

No. 10
Owned by Lambda (Λ-11), Nu (v-13), and Mu (μ-12). Its form is that of a huge sword that can transform into armor; it is actually the murakumo units true form. Murakumo means "Gathering Clouds", derived from Ame no Murakumo no Tsurugi (Kusanagi-no-Tsurugi), the "Sword of the Gathering Clouds of Heaven".
 * Shinki: Murakumo