Demon King of the Sixth Heaven

Demon King of the Sixth Heaven is an special anti-magical, anti-divine and anti-demonic ability created by Ichijou Tsukino of Berolina Gremory's peerage, using the transcendent Sword Ix. By combining the divine, demonic and dragonic properties of the spirits residing inside his Boosted Gear, Ichijou is able to create a zone of "Absolute Zero", similar to an Absolute Terror Zone, used for desperate situations and as a last resort.

Summary
One of the last supporting abilities created by Ichijou and used as a Last Resort, Demon King of the Sixth Heaven is an ability thought by Ichijou after the events of the Vampire Conference Arc. Instead of relying on the breasts or weaknesses of his adversaries, this ability condenses and focus instead in their major strengths such as inherite skills, Sacred Gears, innate abilities or typical of their race, and how to make them be rented useless in a battlefield, such low-leveled move earning the nickname "The most cowardly move".

Abilities
By combining the demonic origin of Yagura Gremory's powers and Ophelia's divine powers plus the [PENETRATE] ability of his Boosted Gear, Ichijou embeds his sword Ix with a mix of both powers, in such harmony and control thanks to Ophelia's ability, until it reaches a point of total "Zero" between the two conflicting energies, in which Ichijou launches Ix into the air and make it nail on the ground. Once nailed, Ix will then proceed to use Ddraig's [PENETRATE] ability to rip space and dimensions and then embued it with the resulting energy between Yagura's and Ophelia's, the only way to end it is by removing the sword from its final place.

Similar to an ATZ, the resulting empty space created by the sword will be filled with "Zero" energy, and then create a dome-like space in which all forms of energy, be demonic, angelic, magical or even divine will be neglected by being balanced and erased with the lingering Zero energy in the zone of influence as long as Ix is craved on the area. Likewise, things such as divine protection, luck-based abilities, Touki or even natural weaknesses won't work, meaning demon swords won't have any effects besides physical ones on angels and vice-versa, and all forms of invunerability will be negated. In other words, the victims within Demon King of the Sixth Heaven become "just flesh and bones" and rely on their own bodies and abilties with weapons. Demon King of the Sixth Heaven can also be used as a defensive skill, since once in contact with the dome, all forms of magic with dissipate within it, leaving their possible victims inside of it unharmed.

Drawbacks
Naturally, Ichijou is also prone to become victim of the de-powering abilities of Demon King of the Sixth Heaven, meaning he won't be able to rely on any abilities of his Sacred Gear or his devil magic, even more that he needs to sacrifice Ix's uses for it to take shape. While those within the realms of such skill won't be able to use their signature abilties in it, it is only limited to such, meaning physically stronger opponents still pose a threat to weaker ones even without their powers, likewise demonic or holy swords can still cut through flesh and bones if hit like any bladed weapon would.

Moreover, creatures and a certain number of powerful individuals can break the spell casted on the surroundings by simply overriding the Zero energy in the air with their own immense stock of power, Ichijou commenting a Ultimate-class devil might be able to break Demon King of the Sixth Heaven with a certain ease.

Trivia

 * Images based on Rider of Red/Achilles' Noble Phantasm Diatrekhōn Astēr Lonkhē from the Fate Series.
 * The name of the ability is a reference to Mara, a Buddhist demon associated with death, rebirth and desire and the personification of the forces antagonistic to enlightenment and who that tempted Prince Siddhartha by trying to seduce him with the vision of beautiful women. The title itself is associated with a demon of the realm of pleasure that tries to dissociate a pratictioner in reaching enlightment.
 * This is, so far, the only ability created by Ichijou that retains it's original japanese reading.