Corrupted Excalibur

The Corrupted Excalibur is the reaction to Excalibur's action. It is equal in power to Excalibur, but instead of being a holy sword, it is demonic. It was formerly wielded by Mordred and is now kept within a field of holy magic in Heaven.

Summary
The Corrupted Excalibur was the sword that Mordred wielded in battle against King Arthur Pendragon. According to legend, it was formed from the outburst of energy that the creation of Excalibur released. It was originally just a normal Holy Sword, but after Mordred discovered it, he stole it and used the magical energy of captured devils to make the sword strong enough to counter Excalibur. Following the fight between Mordred and King Arthur, the sword was lost for centuries before being found by Ajuka Beelzebub in the mid-1900s. It had been buried deep beneath the ruins of King Arthur's castle, in the hope that it would be lost forever.

Following the formation of the alliance between the Three Factions, the angels and devils exchanged Excalibur and its corrupted twin, each taking a sword. The devils sealed Excalibur away with demonic magic, and the angels sealed the Corrupted Excalibur away with holy magic.

Appearance
The Corrupted Excalibur resembles one of the forms of its twin, but with a living eye in the crossguard, which is shaped like a pair of wings. It can also change at the will of its wielder, but no other form has ever been seen.

Abilities
Demonic Magic: Excalibur acts as an arc of demonic magic, especially deadly to angels. It allows the wielder to cast demonic spells and curses, even if that is not their affinity.

Destructive Force: Excalibur has the ability to unleash pure, destructive power that can easily shatter anything it comes into contact with, powerful enough to create huge craters.

Mimicry: Excalibur has the ability to transform itself into any weapon and morph into any shape, size, and material its wielder desires. It can even be turned into any regular object. It is even able to create multiple life-like sized copies of a living being.

Speed Enhancement: Excalibur grants the wielder incredibly enhanced speed, fast enough to create after images of oneself. The sword also seems to give the wielder enhanced flexibility, making it easier to avoid attacks at high speed.

Dream/Illusion Manipulation: Excalibur allows the wielder to cast illusions and manipulate dreams.

Invisibility: Excalibur can turn itself and/or the wielder invisible.

Total Control: Excalibur grants the wielder the power to manipulate anything, be it matter, energy or even ether if he or she wishes. With time, the controlled opponent/object will gradually lose their will and eventually become fully subjugated.

Trivia

 * The weapon is based off the "evil" Soul Calibur from one of the SC games (II, I think).
 * Zach has seen the Corrupted Excalibur for himself but was not allowed to go close to it for clear reasons ("They seem to think I'd try and take it." ~ Zach).
 * Apparently, the Holy Grail's magic could eliminate the powers of the Corrupted Excalibur.
 * The People of the Black Shrine want the Corrupted Excalibur, but for some reason are uninterested in Excalibur itself.