Mirrodin's Core

Mirrodin's Core, called Tav Rakshan (Hall of the Eternal Sun) by the leonin, is a massive globular space within Mirrodin, utilized by Memnarch to control the outer world.

Mirrodin's Core can only be approached through five lacunae, one in each land of Mirrodin. At the center of the globular space, suspended in the air, is a blinding circle of bright light. This ball of pure mana is known as the Mana Core. Mirrodin's Core provides a brilliant and otherworldly sight, with shining metallic surfaces everywhere, reflecting the intense light of the Mana Core. Living in it were many hundreds of Memnarch's artifact creatures and constructs. The Panopticon, once Memnarch's lair, is also located here, just below the beaming Mana Core.

It was from the Mana Core that the four suns emerged into the sky in Mirrodin's distant past, with the fifth being a recent addition. This event puzzled both the plane's Guardian and its denizens, eventually leading to legends about the nature of the five satellites. Mycosynth towers also dot the metal innards of the plane, though their arrival is also something of a mystery. The truth is that the mycosynth was a product of the glistening oil Karn had unintentionally brought to the plane, which created the mycosynth as a first step towards Phyrexianizing it. The suns' existence was a result of Dominaria's time rifts, which destabilized Mirrodin's core, causing it to gradually discharge the five orbs of mana.

During the Phyrexian takeover of Mirrodin, the Phyrexians drilled holes into the core and it became one of the three spheres of New Phyrexia.