Mestral protection
Mestral protection is a binent spell that shields its subject from the mestral effects that pervade most of the godworld. It may be cast either rhegally or epasmatically, to affect an area or a specific object. Cast on an area, the spell will cause the conditions of the current mester to be preserved as long as the spell lasts, even if many mesters, or even years, pass in the meanwhile. Cast on a person or object, it will prevent that person from being transformed by the mestral effects; a mestral turnskin under the effects of the spell, for instance, will not take their other form during the mester when they normally would.
The spell, of course, has limitations. It only protects its subject against the direct effects of the mester, not the indirect effects. A rhegal application of the spell may prevent blades from appearing in that area during Canoan, but it will not prevent blades that manifested in neighboring areas from moving there, nor will an epasmatic application prevent the subject from being cut by blades. Similarly, a rhegal application will prevent the mestral mist from manifesting during Bajiber, but an epasmatic application will not protect someone inhaling the mist from alecy. A rhegal application will, however, protect its contents as long as they remain within the rhegus; a person within a rhegus of mestral protection will not be ænified during Gurunda or Derean as long as they remain within the rhegus, but will immediately turn to metal should they leave the rhegus during those mesters.
Uses
As the spell's name implies, the most usual application of the mestral protection spell is to protect someone against the nocumental effects of a mester—either protecting an area from change, or protecting one or more creatures or objects from mestral transformations. For this reason, the spell is most often cast, particularly rhegally, during mesters in which conditions are relatively "normal": Farinda, Calian, and especially Jiricin. Sometimes it is cast in other mesters to preserve more exotic states, however; some people may enjoy perpetuating the polychromy and unusual textures of Gandagabian or the inebriant mists of Bajiber.
The spell can, however, be applied to queder ends. It can, after all, fix negative conditions as well as positive. For instance, though when cast outside the Bunanj the spell would protect a subject from ænifaction, if cast during one of the Mortal Mesters on a subject already ænified, the spell will prevent them from returning to fleshy form as they normally would at the end of the mester. This particular eventuality is one that might seldom come up, since most of one's enemies will themselves be ænified during those mesters, but there are other equally maleficent possibilities for the spell: cast on a subject just before Lulean, for instance, it would prevent the subject from gaining the ability to breathe underwater, likely resulting in their drowning; cast on an area during Jijian, it would cloak that area in persistent darkness.
Development
Although it's commonly believed that the mestral protection spell is responsible for the immunity of the Golden Cities and their contents to mestral transformation, in fact the Golden Cities predate the development of this spell, and were evidently brought about by other means—most likely by some now lost paracarminical method. In fact, there is evidence that the Golden Cities, through their "rose league", actively worked to suppress knowledge of the spell, the better presumably to maintain their own monopoly on freedom from mestral hindrances.
The mestral protection spell was probably created about four thousand years ago. It is commonly believed to have been invented by the mage Matkanas, but virtually any magic of unclear provenance from around that time tends to be attributed to him, and there are several reasons for believing the attribution unlikely in this case, not the least of which is that Matkanas is not known to have been proficient in binentry.
In any case, whoever originally invented it, the spell didn't become widely used until the Blue Rebellion, when the people of Laornia rose up against the empire of Ari. How exactly the Laornians unearthed the spell remains undetermined, but their employment of the spell brought it back to prominence, and since then, though it has never been common and its use has waxed and waned, it has never returned to the obscurity in which it once languished.
Entailments
Mages have developed a number of entailments that help them cast the mestral protection spell. Like many binent spells, it is often cast with the aid of dances and gesticulations, in this spell's case usually involving a fourteen-step circular dance (presumably in imitation of the fourteen mesters). Blood, too, is often used, as in many binent spells, but other material reagents are also common, generally comprising at least three substances or objects preserved from different mesters, such as a bottle of badgebrew, a piece of buckstone, a rimeblade.
Corollaries
The mestral protection spell is often accompanied by a slight crackling noise, and a flicker of the subject, showing briefly (and illusorily) what it would look like in different mesters. Other corollaries vary depending on the mester. In Gandagabian, the object's color often briefly brightens. In Canoan, there is a noise like a grinding blade. In Bajiber, the object seems briefly blurred. In Gurunda, there is a brief smell of ozone, and in Derean of rust. The spell's casting in Bukoan is accompanied by a taste in the mouth both earthy and acidic; in Fansinda there is a brief sense of vertigo. WHen cast in Lulean, the spell is often associated with a small explosion of bubbles if cast underwater, or of water droplets if cast in air. In Calian, the object shimmers with a green hue (or a brighter green hue, if already green), and in Hauau there is a whistling sound audible even over the everpresent wind. In Worohue, the spell's casting brings a feeling of sluggishness and thickness; in Nunean, a whooshing sound. In Farinda, the subject is surrounded by a warm, yellow glow; in Ienoan the subject glistens; and in Jijian the spell brings a momentary sensation of increased weight. Finally, in Jiricin the spell's corollary is a temporary bleaching of the subject and its surroundings, which appear wan and whitish for a split second when the spell is cast.