[@thewizardguy]

She was wrong, in fact, but still close. 

Corban was not aware of her magical sight, but he pre-empted it; It was incredibly rare that one who absorbed themselves into the arcane would not at least recognize its various flows and states. Experience simply made Corban cautious. Speaking of which, he had also pre-empted that it would have no effect on her. However, for different reasons than the truth.

It was part of his profession and a result of his experience that made him so unnaturally attuned to magic and the complexities and nuances of its principles. This of course extended to free magic. He was more than prepared for her shadow blast.

In fact, he counted on it.

Wide blasts were powerful, but unfocused. With their spread came a simpler diffusion. Speak of wasted energy, sheesh! Just as the viscous shade would bubble and froth forth, two four-foot thick slabs of blue-crusted earth would snake up before and behind him at 135 degree angles in a pyramidal tent shape.
Corban bent low so as to be beneath them when the blast would meet his bulwark.

BOOM!

As blast would meet wall the former would be deflected upward by the shield's angle... But not before a violent explosion would meet the she-mage in the face at point-blank range. Except Corban's explosion was precise. Something hard to achieve with those pesky things. 

Call it fate or divine decree, but Corban held total dominion over carbon. Go figure. The carbon rich earth that acted as his shield metabolized the energy erupting from their interaction to facilitate a transmutation, converting the first several layers into diamond-loaded octanitrocubane. Which happens to be the most powerful non-nuclear explosive known to man. The blast would plume outward, though not disseminating into a wide arc, but instead was channeled into a focused wave-beam shape that hid (now)superheated, magically insulated crystals. It would shear and blast the woman, and probably several yards of earth behind her into a quite unseenly mess.

He had effectively used her blast to the face to make an even larger blast to [i]her[/i] face! If she still was back there gloating, Corban sure couldn't hear it over the sound of of his molecular beam-buckshot. 

As steaming shells collapsed back to the earth the mage would rise from it, leaping backward several yards as he shed the carbon-ore from his flesh all the while into miniscule particulates. His hand still bled evermore bubble-metal.