The Black Maw

The ‘Black’ Maw that Swallows All (nu – lp – eu – bf – zuh – ei – jkv – iu – a – xw) (清濁万象を呑み干す「漆黒」の顎 Seidaku banshō o nomihosu `shikkoku' no ago) is an special Material, considered the worst of all monsters. The Black Maw automatically replaces a summoner's current Material if they violate one of the Taboos of the summoning ceremony. It was later revealed by Kyousuke Shiroyama to be the same existence as the White Queen.

Appearance
The Black Maw normally looks like a vortex of pitch-black slime, capable of rising up like a snak.The very top of the tornado looks like a maw absolutely filled with fangs.

However, when summoned by Kyousuke, the vortex of slime parts to reveal the Black Maw's true form, a pitch black version of the White Queen with pure white eyes.

Personality
The Black Maw normally displays no apparent personality whatsoever, appearing as a vortex of pitch black slime filled with teeth that simply devours the summoner who has violated a Taboo. However, when summoned by Kyousuke, the Black Maw appeared incredibly ecstasic about the chance to eat her "dear brother", as she's the other side of the White Queen and as obsessed with Kyousuke as the normal White Queen is.

Light Novel Volume 01
The Black Maw first appears in the story when she's Renge Meinokawa causes one of the Guard of Honor's summoner to violate Taboo 1. Kyousuke would later explain to Renge about the relationship between the White Queen and the Black Maw. Kyousuke would later intentionally summon it to face the White Queen summoned by Guard of Honor. The Black Maw barely won the fight, but before she could fully devour Kyousuke he managed to change his Material and save his own life.

Abilities
The Black Maw is an special Material that appears to punish the summoner who violates a Taboo, thus, it can bypass the protective circle of a summoner to eat them with her maw filled with fangs. After devouring the summoner, it will dissappear on its own. As the White Queen's other side, the Black Maw is equally as powerful as the Queen, as seen by their fight which the Black Maw barely won, losing all her limbs in the process. Unlike the White Queen who manipulates light, the Black Maw appears to be capable of manipulating darkness.

A summoner can hit a Petal into a Spot when the Black Maw appears to change it into another Material. However, since the Black Maw normally devours the summoner as soon as it appears, this is a very rare ocurrence.