Devil King Sword

Devil King Sword (魔王剣 Maoken) The Devil King Sword is a fiendish weapon of incredible power forged by Kaguya and is the evil counterpart of the Supreme King Sword. It looks like a huge, double-edged longsword with a black blade and white borders. The handle is black and rectangular, and with a white tip. The hilt itself is composed by a round body shaped like a fiendish head (with the open mouth serving as a power gauge) and two horn-shaped arms protunding to the sides and adorned by what seems to be black fur. The blade of the weapon is slightly larger at the bottom and sports a hook near the hilt. This blade can turn the evil spirit of the user into energy blasts capable of erasing all life from the Earth. When fully unleashed the blade turns into black energy.

According to their power gauge, It has three attack forms:

the Crescent Slash It resembles the Wind Blade in appearance, only black in colour and more powerful in destructive capacity. This attack can easily destroy one of the 8 heads of a dragon the size of Japan.

the Half-Moon Slash Onimaru concentrates more dark energy into a giant dark sphere which he then throws at his enemy. This attack can easily destroy an island, making an explosion that can be seen from the atmosphere.

the Full-Moon Slash The Maou-ken’s strongest attack, capable of destroying a planet in an instant (image). This attack is similar to the Half-Moon Slash, only lighter in colour and much more powerful.