Seventh Holy Scripture

The conceptual armament that Ciel is authorized to carry. An iron hammer created by Christianity in order to renounce the heretical doctrine of reincarnation.
…Although, if reincarnation didn’t really exist then it seems like it would be kind of unnecessary to prepare an anti-reincarnation weapon, right?
Originally created by felling a miraculous beast said to consume souls, then using its horn as a key. The surface of the horn is inscribed with tightly-packed complaints about how “reincarnation is really lame.”
It was sanctified over the course of many years, but eventually fell into Ciel’s hands.
“A horn!? That’s not practical at all. The higher-ups are totally out of touch!”
Unable to hold herself back, she set about improving it.
At any rate, since it’s been almost a thousand years since it was first created, it even has an elemental living within it… though the essence of its personality may have been a bit warped by Ciel’s remodeling.

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Tsukihime Data Collection: Tsukihime Dictionary
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Ciel’s conceptual weapon. The iron hammer of reincarnation judgement. More than 1,000 years have passed since it was first created, and a spirit resides within (the figure you see when Ciel appears is the spirit). The spirit is called Seven, and she takes care of a wide range of things for Ciel, from sewing to being the target of Ciel’s stress relief. The spirit is also called Nanako (refer to Kagetsu Tohya for details).

MB Official Strategy Guide: Melty Blood Glossary
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The conceptual armament that Ciel is authorized to carry. An iron hammer created by the Church in order to renounce the heretical doctrine of reincarnation.
It was created by felling a miraculous beast said to consume souls, then using its horn as a key. The surface of the horn is inscribed with tightly-packed complaints about how “reincarnation is really lame.”
Since it’s been almost a thousand years since it was first created, it even has an elemental living within it.
It was sanctified over the course of many years, but eventually fell into Ciel’s hands.
“A horn!? That’s not practical at all. The higher-ups are totally out of touch!”
Unable to hold herself back, she set about improving it, and because of that the Scripture’s elemental ended up having the essence of its personality warped.
Before Ciel remodeled it, it was only effective against spiritual entities. Now, however, it has been transformed into a lump of iron that can pound a vampire to death with its physical attack power alone. It has a gross weight of 60 kilograms, and a maximum weight of twice that with optional attachments. It’s a… Gatling scripture!?

Tsukihime Dokuhon Plus Period: Tsukihime Dictionary Revised
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Ciel’s Arc Drive.
The conceptual armament that Ciel is authorized to carry. Although it is called a scripture, it’s actually an enormous pile bunker.
An iron hammer created by the Church in order to renounce the heretical doctrine of reincarnation. Over a millennium has passed since it was first forged, and there’s even an elemental dwelling within it, but…
Before Ciel remodeled it, it was only effective against spiritual entities. Now, however, it has been transformed into a lump of iron that can pound a vampire to death with its physical attack power alone. It has a gross weight of 60 kilograms, and a maximum weight of twice that with optional attachments.
During Ciel’s Arc Drive, she drives the stake into her opponent. Afterward, what is ejected from the magazine is not an empty cartridge, but pages of the holy scripture. For vampires, this is no different from being directly injected with the holy scripture itself. There is no doubt that it is a surefire “Immortal Killer.”

MB Act Cadenza PS2 Manual: Tsukihime Dictionary
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A conceptual armament owned by everyone’s favorite Ciel-senpai. It weighs in at 60kg. It goes through some rough times being abandoned after Ciel forgets it at Ahnenerbe and doesn’t come back for it. For some reason, Nanako has developed a good relationship with Hibiki, who can see her. Just as Nanako was getting on bad terms with Mobile Phone-san, Ciel suddenly appeared on the scene and retrieved her with a rhythmical hop-skip and jingle. Even though she is an idiot.

HibiChika Complete Capture Book: Mahou Tsukai no Hako Small Encylopedia
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A holy relic that can never be taken off its premises, made for the Holy Church to represent the authority of the Lord, and whose user was absent for a long time.
The embodiment of an artificially made miracle.
A Conceptual Weapon that was put together as a scripture a thousand years ago, by luring one of the scarce Phantasmal Species that remained on this world, and forging divine steel by burning it along with the maiden who acted as the catalyst in a furnace.
Every single primary factor of death humans are burdened with, including the crushing of the soul ——— for instance beheading, is recorded, and the divine steel continues chanting a baptism of admonishment with characteristic vibrations.
The conjoined form of the six armaments: dual guns, bayonet, greatsword, armor, and the core, founded on the horn of a unicorn, is operated as an Anti-Vampire Mobile Armament, and through further deployment it can be transformed into a siege ballista.

Tsukihime Material I: Tsukihime Work Glossary