Shiv
The island of Shiv is the most powerful source of red mana on Dominaria. It lies on the northeastern part of the string of continents of which Jamuraa also forms a part. An inhospitable volcanic landmass, Shiv sits in a deep-ocean "Ring of Fire" which fuels the coastal waters to near boiling point. Only the viashino lizard-folk know the secrets of how to navigate these inhospitable waters, much to the ire of the Shivans. Shiv’s inhabitants include the viashino, goblins, the nomadic Ghitu and of course the Shivan dragons.
History of Shiv
During the ancient times of the Thran, an outpost of this large empire was located on Shiv, a Mana Rig used to produce powerstones. The structure remained standing for ages after the fall of the Thran. The descendants of the goblin slaves that operated the rig forgot how it was supposed to be used, but created a form of religion surrounding the structure.
During his studies on Tolaria, Urza discovered an amulet of Thran-steel one of his students, Jhoira of the Ghitu, carried. Hoping to use it in his quest against Phyrexia, Urza traveled to the volcanic island and managed to settle with the viashino living by the Rig by making peace with the dragon Gherridarigaaz, and he managed to persuade the goblins to work with viashino for his cause. From that time on the Rig produced many powerstones for his Legacy.
When the Phyrexian Invasion broke out, the Rig was used offensively by Jhoira against the Phyrexians, much to Urza's chagrin; but her old friend, the planeswalker Teferi, had decided he’d rather flee than fight and wanted her to go along with him. Teferi phased out a large chunk of Shiv along with Jhoira and part of the Mana Rig. During this time the Primeval Dragon of Shiv, Rhammidarigaaz, who had been reborn as Gherridarigaaz's son, discovered his origin and started awakening the other dragons.
Shiv suffered horribly after the devastation left in the wake of the Phyrexian Invasion and the drought of mana caused by the time rifts. Teferi successfully managed to return Shiv to its complete and whole form at the expense of his planeswalker spark.