Blow you all to hell
Anabstercorian stares in to the sun. Illithid near him, powerful mages with immense arcane skill, tremble in fear, looking directly at that which they have long loathed.
They are standing on its surface. The air around them is a plasma, the electrons blasted from their nuclei. Only 9th level spells of Protection From Elements (Fire) and Protection From Radiation save them from instantaneous vaporization. But the magic is great - The power is not blocked, but simply redirected in to the Positive Energy Plane where it has no noticable effect.
<< That is power, my friends, >> speaks Anabstercorian. << The power to give life, and the power to take it away. This is where power comes from. Follow me. >>
And he teleports them all to the Core.
You cannot see anything but White in the Core of a sun. Deeper Darkness spells wink out like flimsy gauze thrown over a bonfire. Prismatic Spheres collapse in to their component phlogiston instantaneously. But certain combinations of spells can allow an entity to exist here, if only for an hour or so.
Anabstercorian and the other Illithid are instantly struck blind. They clutch their eyes, their hands swimming through the super-heated plasma like smoke. They wince and bear up, preparing.
<< Begin. >>
They cannot create a Gate to Oerth from here, for simple reasons. A Gate spell is actually a highly distorted sphere, and resists the flow of energy - Those who had the misfortune to be standing directly in front of the gate would be blinded by the light, but little else.
But it is not hard to Teleport Without Error several hundred pounds of fusing hydrogen to the surface of a planet.
This is what they do. And they are doing it with wands crafted by Wayfarers Guildsmen. The fabric of space pops off in to a neat bubble, separate from the flow of time, and moves to the surface of Oerth, over a vast horde of warriors, Red and Living. It ejects its contents, and the warriors are instantly reduced to char.
They do this until they have no more power left in them, and then they return to the Rockjammers. Anabstercorian waits for the next shift of mages to join him, and they return, bombarding the surface of Oerth with stellar plasma.
Elsewhere, the Neothelid, enormous tentacled worms over fifty feet long with immense psionic power, have been altered for space travel and Dominated by Anabstercorian. They wind their sinuous bodies around the largest unused asteroids that the Army of Darkness could find, easily 1000 megaton explosions, and, using telekinesis, slowly begin to drag the massive bulks toward Oerth.
<< The Red Army is a rot. A lesion that must be treated. We shall cauterize the surface of Oerth, and sear the wound shut with molten lava and powdered stone. >>