Cita:Island Guard (lit., "district guards")
An organization of armed policemen tasked with the maintaining of peace and order among the demons who inhabit the island. Island Guards are equipped with protective clothing and weapons designed to counter demons in combat. Among their main duties include the protection of Itogashima's primary facilities, suppression of rogue magic attacks, and the supervision of attack mage bureaus and factions. The Metropolitan Police Department is supposed to manage the activities of the Island Guard, but in fact, the Manmade Island Management Corporation uses them as a private armed group of sorts.

Itogashima
A manmade island situated 330 km south of Tokyo. Itogashima Island is part of the Tokyo Metropolitan Area as one of its districts. However, this island, whose population is composed of demons, is actually under an independent administration by the Manmade Island Management Corporation. Population is about 560,000. The island is composed of four large floating structures with a north-south-east-west configuration, and these islands are connected together through the central island, Keystone Gate. Climate in Itogashima is generally warm, with a midwinter average temperature exceeding 20 degrees Celsius.

Vampire
A species of demons. Strictly speaking, vampires are the blood relatives of primogenitors. Vampires share a similar body composition with humans, however, they possess very high self-regeneration abilities due to their possession of "negative lifeforce". Also, they call forth familiars into itself unlike other demons, allowing the vampire to acquire that familiar's abilities. On the other hand, their bodies are considerably frail, and bullets made from precious metals and sunlight are among vampires' many weaknesses.
There are many theories regarding vampires and their distinctions with humans, but the topic remains a mystery to many.

Vampiric Instinct
The instinctive desire characteristic to all vampires — the desire to suck the blood of the opposite sex. It manifests in the form of a feeling of thirst and destructive behavior, but in many cases, it is triggered by sexual desire.

Familiar
Beasts summoned by vampires from the underworld. Has the ability to call forth various supernatural phenomena and can give its host great power. However, this great power consumes lifeforce, a feat that only those with infinite "negative lifeforce" like vampires can maintain.

Sword Shaman (pun on Kan'nagi, lit., "shaman")
Attack mages affiliated to the Lion King Organization. Simply put, shrine maidens who wield swords, in a sense. Their strong point lies in using spirits to predict the immediate future, and they also possess great combat ability. Their duties mainly involve the elimination of demons and demonic beasts. Sword shamans number to about 30 people, including Yukina Himeragi.

Attack Mage
The general term used for various magic-related occupations such as practitioners of magic, sorcery and wizardry and those who make a living out of killing rogue magic-users and demonic beasts. Formerly called as "exorcists". The League of Attack Mages issues a qualification certificate (C-card) to all attack mages.

Saikai Academy
A municipal coed integrated school system located within Itogashima City. The middle school is composed of 150 students in 5 sections per year, while the high school is composed of 240 students in 8 sections per year, totaling to about 1200 students. About 50 students in the school are demons. The curriculum used by the school is almost the same as in the mainland's senior high school curriculum.

Lion King Organization ("shishi" also refers to the left-hand guardian dog in Shinto shrines, "shishiou" is used in Japanese to denote kings with "the Lion" as a title, like William the I of Scotland or Louis VIII of France)
A secret military agency established by the National Public Safety Commission. Its chief duties involve the prevention of large-scale magical incidents and acts of terrorism, as well as information gathering and the formulation of strategies in combat.

Schneewaltzer (German: schnee = "snow", waltzer = "one who dances the waltz", Japanese: lit., "Offensive Exorcising Mechanical Spear #7")
A silver-colored long spear entirely made up of metal — the secret weapon of the Lion King Organization. It is a spear which uses divine vibrations as a driving force to nullify magical energy, allowing the destruction of magical barriers.

Therianthrope

Primogenitor/Progenitor

Sekkarou (lit., "snowy haze wolf")
The name inscribed in the Schneewaltzer lent to Yukina Himeragi.

Takagami-no-mori
A lower-branch organization affiliated with the Lion King Organization. It gathers orphans holding magical power from across the country and trains them into attack mages. Yukina and Sayaka were raised from this organization. It is located in Mt. Ooe in Kyoto, known in folklore for the demon Shuten-douji. Training is harsh, but the atmosphere is familial and inhuman abuse doesn't seem to be practiced here. Those who pass the training are given duties of magic investigation and relatively mundane tasks, given the titles Sword Shaman and 舞威媛 for the elites.

D-type
A term used to describe first-degree blood relatives of a Primogenitor. Second-degree relatives are called G-type, and third-degree relatives are called T-type. [D=Dracula, G=???, T=Vlad Tepes?]

Dominion (lit., "Empire of the Night")
A country governed by demons, particularly one of three self-governing countries led by Primogenitors. Although demons can live in Dominions, most of the population of Dominions are composed of humans. The rights of the people vary amongst Dominions.

Demon Registration Card


Demon District

Kingdom of Lotharingia
A constitutional monarchy located in Europe. Has a strong relation with the Western Orthodox Church, with the Lotharingian Orthodox Church serving as the country's most influential sect. Lotharingia is a world-leading industralized nation, famous in precision instruments and automotive industries. However, due to the conflicts situated near the borders of Lotharingia, the country is slowly receiving more migrants, causing frictions amongst citizens and raising social issues.

Rhododactylos (Greek, lit., "rose fingers" or "rose thorns")
The manmade familiar merged into the artificial body of Astarte. First appeared as a pair of massive arms that manifest on Astarte's shoulders, it takes on an appearance similar to a golem in its complete form. Astarte can still be seen inside Rhododactylos in this form, positioned in the chest area of the familiar, with a translucent shell separating Astarte from the outside.