Lesser Key of Solomon

The Lesser Key of Solomon (, Ressā Kī Ofu Soromon; lit. "Occultism of the Tyrannical Demon King") is considered to be something legendary, its existence known throughout creation — seen and validated throughout various points in history. The magic is highly-feared amongst various races, especially those of demon kind — seeing how its affects are mainly aimed at them; it's considered to be on-par with the Ancient Magics of the Thirteen Otherworldly Virtues, as it's one of the few things that's derived from God himself — a personification of his "justice over all forms of evil".

As one of the oldest magics in creation, it's a form of Holder Magic — usable through its signature ring, a form of Subspecies Magic as it's derived from Ring Magic, and dubbed as a Lost Magic due to its age and power. Various historians, rulers, and government officials recognize this as an obscure form of the Black Arts, its effects being apparent and fairly potent — even amongst its kind. This branded it also as a Forbidden Magic, its use said to have brought extreme amounts of havoc — especially when in the hands of impure. Like some known magics, this magic is known by many names — its most common one being "Devil's Sovereignty Magic" (閻魔の支配権魔法, Enma no Shihaiken Mahō).

One of the most interesting things about this magic is that it can't naturally be learned, as the ring itself chooses the wielder — most of whom were those "born out of vice"; this gives it a sentient nature, something that's only seen in the most powerful of magics and magical tools. It's current user is Kurenai Sarutobi — one of the oldest and most powerful users to-date; this magic, along with use of his Take-Over are some of the few reasons that he's feared by various individuals and hunted down by Angels and Devil Slayers alike.

Trivia

 * This is somewhat based on a similar concept from the anime/manga series, Makai Ouji: Devil and Realist — something the author took a liking too mainly because of its character designs and concepts.
 * The  is actually an obscure book of demonology that's split into five sections — each one listing a certain amount of demons and occult manners; it's considered to be based on — the King of Israel, the wisest man during his time and son of previous King, David. It's believed that he was also able to subjugate many demons through his ring (seen in modern occultism, acting as one of its primary symbols) and wisdom — both of which were given unto him by God, which served as one of the many reasons for his downfall.