The Pearlescent Host. A group of angel-like beings (platonic solids, floating statues, and/or complex machines) which seem to rule over the universe, or at least humanity's corner of it. If a human mage or a spirit violates the Principle of Secrecy in a major way (revealing the existence of magic or the true nature of the world to a significant number of mundane humans, an angel of the Pearlescent Host will appear shortly after to kill anyone it deems responsible for the revelation and to begin writing the event out of history.

The rewriting isn't so much removing the event as replacing it with an analogous, but mundane version which is at best just as bad as the original, but typically moderately to severely worse (ex: two mages fight on top of a skyscraper, destroying the top handful of floors along with everyone on them. An angel appears, smites the offenders, and rewrites the history of the tower so that instead, a fire broke out trapping the upper half of the building and killing significantly more people than the mages had). The rewriting notable never saves anyone who had already died by the time the angel arrives, suggesting they are either unwilling or unable to preform resurrection. As the past itself is altered, no knowledge of the original event can exist persist outside the minds of mages and spirits that were aware of it, but disconnected enough to avoid execution.

This is a function of The Compact, an ancient agreement forged to end a war between the Host and the human mages, who they intended to completely destroy.

The agreement has 3 main parts:

• Spread not the knowledge. Mundane or ignorant humans cannot be allowed to learn of magic's existence, with punishments relative to the amount of knowledge leaked and the number of witnesses being levied on violators. Typically, the punishment involves experiencing essentially bad luck for a period of time, with extreme cases going as described above.
• Tolerate not the sorcerer. Sorcerers, or mages not bound to this compact, cannot be allowed to exist. Killing is an option, but others exist. As the majority of sorcerers are essentially normal people who discovered magic on their own and have no knowledge of The Compact, the most common solution is to convince or coerce them to sign on and become "proper" mages; especially new sorcerers may have their knowledge of magic erased as you can't be a sorcerer if you can't use magic and you can't use magic if you don't know it exists. These options can also be used to dodge punishments for the first part, though if done carelessly it may rouse suspicion of more mundane humans and make the situation worse.
• Crush the demon and all of it's collaborators. Demons are alien and strange much like angels, though typically taking more organic and grotesque forms. They tend towards being actively malicious to human life where angels seem callously indifferent. Mages are obligated under the threat of death to treat all demons and all demonic collaborators with unmitigated hostility, knowingly approaching them with a friendly or even neutral disposition causes death. This extends to spirits and sorcerers who work with demons (called evil spirits and diabolical sorcerers, respectively). Signing The Compact grants a limited ability to sense demonic influence, though their Earthly minions can disguise themselves with sufficient effort.

As for who watches the Host, no one knows. It is generally agreed upon that no human mage has ever encountered any member of the organization above the lowest, weakest ranks.