Venuzdonoa

"Venuzdonoa, the Abolisher of Reason, reduces all logic to null. There is no point in thinking of what, how, or why."

- Anos to Melheis Boran in "The Demon King's True Power"

Venuzdonoa, the Abolisher of Reason (理滅剣ヴェヌズドノア), is the demon sword of Anos Voldigoad which can destroy anything that exists, including the order of the world. It is a sword which Anos rarely uses, and its existence is mostly unknown because those who witness it are permanently annihilated.

Appearance
When Venuzdonoa is summoned, countless black runes are inscribed on Demon Castle Delsgade, which serves as a giant three-dimensional magic circle. Innumerable black particles of light gather to form a shadow of a sword with no object projecting its shape. When the wielder holds out their hand, the shadow slowly rises from the ground. Once they grasp the hilt, the shadow inverts and reveals a dark longsword. The wielder can also sheathe Venuzdonoa by stabbing it into the ground, causing the sword body to disappear and leave a shadow at their feet.

Great Spirit Arc
After the war between demons and humans was averted, Nosgalia appeared and sought to eliminate Anos and revive Abernyu with the help of the "Child of God". This mysterious figure was eventually revealed to be Misa Iliorogue, who was also the spirit that embodied the legends of the fake Demon King, Avos Dilhevia. Due to her rumors and lore, Avos was able to claim ownership over Delsgade in order to take control of Venuzdonoa.

{{SpoilerSection|id=1| She attempted to defeat Anos with Venuzdonoa but failed after Anos used his Dark Purple Magic Eyes to nullify the sword's power. Afterwards, she frees  to fulfill Nosgalia's mission to restore the order of destruction, but it destroys her instead. After her defeat, Anos saves Misa and regains control of Delsgade and Venuzdonoa.

Dragon God's Country Giordal Arc
During a field trip to Gairadite, Anos met Arcana and Ahid Alobo Agatse, and learned of the Underground World and its current conflicts. During that time, Anos helped Arcana, whose authority was incomplete, by temporarily lending her Venuzdonoa so she could combine it with the Moon of Creation  to create the Sword of the Almighty Livaingirma.

Demon King's Father Arc
Anos later learned that Militia kept his lost memories in artifacts called the Creation Stars Erial. Anos and his group set out to find them. He learned that his real father, Celis Voldigoad, was killed by Graham. Anos fought Graham and destroyed him with Egil Grone Angdroa, but Graham revealed that his true form was nothingness. Anos summoned Delsgade to use Venuzdonoa, but it was incapable of permanently destroying Graham. While Graham's weapon, Befenguzdogma and Venuzdonoa seemed evenly matched, Befenguzdogma was able to destroy Venuzdonoa.

Disaster Abyss World Arc
In a challenge against Kostoria Arzenon, Anos let Kostoria summon Venuzdonoa. Because Sasha regained her power as the Goddess of Destruction by merging with Delsgade, her body and sight became the domain of Delsgade, so she must be present in order to summon Venuzdonoa. She can manifest the sword in her sight via her Magic Eyes of Reason Destruction. Despite Kostoria Arzenon correctly summoning Venuzdonoa, she did not win because of Venuzdonoa destroying reason, and Anos won the challenge.

Later, in a duel between Sasha and Kostoria, Sasha used Venuzdonoa herself, but Kostoria copied Venuzdonoa via her Magic Eyes of Transcription. Both failed to destroy each other, and Sasha's magic power ran out preventing both of them from continuing to use the sword. }}

Abilities
Absolute Destruction: Venuzdonoa can destroy anything, regardless of how tough, eternal, or infinite it is. Even reason itself can be destroyed. The sword can undermine the immortality of gods and prevent their regeneration. Venuzdonoa can nullify spells and reduce them to nothing. By destroying the order of the world, the Abolisher of Reason can slice a target without making contact with it. The sword can even be used outside of combat, for instance, to ensure that wrong answers on a test receive full marks and bonus points. However, order will be restored once the sword is put away, so the effects of Venuzdonoa are temporary.

Weaknesses
Venuzdonoa can only be used near Delsgade which is likely a consequence of Anos sealing Abernyu, the Goddess of Destruction, in Delsgade. This limited the influence of the order of destruction to the vicinity of the castle to stop its immense power from leaking into the world. However, dimensions created by magic are irrelevant as long as the wielder is physically near the castle. Additionally, it is possible to summon Delsgade with origin magic, meaning Venuzdonoa can be used virtually anywhere, but summoning the castle consumes a lot of power and casting the greater spell used to summon Delsgade takes some time. Although Venuzdonoa itself does not have a time limit, the spell used to summon Delsgade has a duration of five minutes. The Abolisher of Reason can only show its true value when held by its wielder, but it can still be used without the wielder holding it in their hands, but it is weaker as a result.