Great Rift
"It is always possible the records are incomplete."
- Proverb of the Azurejays, Scholar-Knights of San Sylvester
This article is incomplete and will require additional work.
The Great Rift is an impressive Gate Storm near the geographical centre of the Shimmering Shore, which is considered the epicentre of the Great Collapse. The storm continually opens wild portals from planes documented and undocumented into the wilderness of this area, and the arcane energies that radiate from it have changed and twisted the landscape almost as much as the creatures who arrive on Ahren through such portals.
The cause of, and solution to, the Great Rift (and indeed, the collapse) are the subject of vigorous study and debate in schools of the learned such as those as Sylvestri Point, Heroka, or Petrenea, with each of the various Magical Traditions of Wisteria putting forward their own explanations, which broadly diverge into one of two major Hypotheses - the Convergence Hypothesis, and the Correspondence Hypothesis.
The Convergence Hypothesis
The Convergence Hypothesis refers to interpretations of the Great Rift which describe it as a purely natural phenomenon, caused by the convergence of planes under the accepted understanding of Cosmology - in other words, a routine and cyclic event. Proponents of these Theories point to the seasonality and fluctuation of the type and intensity of Gate Storms in the Shimmering Shore even before the eruption of the Great Rift.
Proponents of Ars Magica schools who support these theories often point to the known formulae for the motions of the planes, though unsurprisingly this is unconvincing. Convergences happen on relatively routine bases, but there's no example in history of a Gate Storm of this intensity. The theory almost universally held among proponents of the Way of the Elements, and as a result the Convergence Hypothesis is the accepted hypothesis among most mages in the Shimmering Shores.
Those practitioners of the Secrets of Nature who are aware of the problem tend to also subscribe to this theory, but unlike the other schools that tend to subscribe to it, they do not take a fatalistic approach to the problem. Great works of magic have changed the fabric of Cosmology in the past, and could do so again.
No event in recorded history has seen a Gate Storm as bad as the Great Rift, leading some to question the accuracy of the calculations that ascribe this to merely natural causes.
The Correspondence Hypothesis
The unnaturally strong and persistent nature of the Great Rift has lead to a belief among many scholars that the origin is not entirely down to natural processes, and the storm is instead either the result or subject of arcane intervention; the Great Rift was committed, rather than having occurred.
Precise descriptions of this hypothesis are as numerous as the proponents.
Some students of Ars Magica, especially those in Bastonia or with strong ties to the Bastonian Pantheon, believe that the storm is yet another example of the persecution of mortality by the Enemy, with a few blaming San Verus specifically, and believing that the storm is a result of the Mad God of Magic attempting to escape the Abyss. Students of the same school more closely aligned with the High Elven Pantheon may also come to a similar conclusion, instead blaming Hycis Uriris.
This interpretation is also common among followers of Orcish Shamanism, who lie the blame at the feet of angry spirits - usually the same sorts of spirits and outsiders who are appearing from the portals caused by the Great Rift itself. The theory is also common among those without a strong education in Cosmology, as Wisterians of all backgrounds tend to be quick to ascribe to malice what might be mere happenstance.
Some schools of magic in the Shimmering Shore that adhere to versions of the Correspondence Hypothesis place the blame for the incident on Anghara. This is of course vehemently denied by the scholars of the city of Baghar.
As the Gate Storms spun off from the Great Lift may well lead to convergence with any dimension documented in the Cosmology of Ahren, including worlds otherwise unnoted, opponents of the theory criticize it on the grounds that a conspiracy among all the planes to invade Ahren is extremely unlikely, and that none of the Gods which teach an ending to the world teach it in this manner.