The Starwell & The Winds of Magic

After the age of Prometheus the heaven-dragon was felled from the firmament. The cataclysmic star that struck Orr sundered the planes and from it roared the unbridled winds of magic. The frayed dimensions bled into one. Time wandered forward, backward and trampled over itself into a cacophony of alternate dimensions and splinters of the mortal plane. It is impossible to know for certain how many fractures were made, how many perished, or how many remain after this cosmic unraveling, but when at last the planes and the roaring winds were divided again the 'Prime' material plane was given its agency and the site where the heaven-dragon had tore the worlds became known as the Starwell.
The eight winds of magic still flow through the cosmic tear but are splintered by the power of the Spelltowers that surround the Starwell. This opening in space and time is a massive planar storm from which outsiders slip into the material world. Some arrive from the distant, dead planes lost in the splintering of the universe. Other arrive from different timelines, both the past and the future. The Starwell is the most dangerous site in all of Orr, its very presence threatening to rip the seems of the universe open wide to the immutable jaws of chaos.
To prevent the untold disaster of such an event, all of the great civilizations and nations of Orr have signed treaties to never endanger the site or the apparatuses, the Spelltowers of Rizion, which contain its power.
To ensure this treaty is upheld and to protect the Starwell against the outsiders that might slip through it or beings of Orr itself that might seek to threaten its integrity, there exists an order known as The Sable Star lead by a High Sorceress chosen among the greatest wielders of magic in the world. The High Sorceress must complete trials of sorcery and tests of character and temptation designed and left behind by Rizion herself to ascend to this throne of power. None except those who have completed such trials know their exact content, and are sworn to secrecy. The High Sorceress is guarded by an ageless knighthood of magical constructs called the Ravenguard whose loyalty has never wavered. Should any force or any being threaten the Starwell, the High Sorceress possess the power to evoke the ancient magic of the Starwell's treaties which are imbued with the power of World Geas. A spell of domination that can be cast upon entire nations. The World Geas has never been invoked, and its power never tested, and all of Orr prays that there will never be a cause.