Rath was an artificial plane utilized by the Phyrexians as a staging point to invade Dominaria. Created out of Flowstone generated in the central Stronghold, the plane slowly expanded over centuries until it was the same mass as Dominaria itself, at which point it would transpose atop the target plane, carrying its armies directly into the field. As Rath grew, regions of the two planes would overlap briefly, bringing Dominarian inhabitants into this new, hostile environment. Rath was ruled as a Phyrexian fiefdom by appointed Evincar, though an effective uprising was led by Eladamri just before the planar overlay.
Rath was the setting for the Tempest, Stronghold, Exodus, and Nemesis expansions.