What is a Void Mage?

[Anonymoose]

As far as I can tell, the basics are thematically related to Black Magic incidentally through Mhach, but the two disciplines are far from synonymous, nor are they necessarily mutually exclusive.

VOIDMAGICKS

Although the Mhachi were known masters of black magic, the extent of their power was not limited to Shatotto's school of spellcraft. Toward the autumn years of the Fifth Astral Era, the civilization had begun perfecting voidmagicks—the summoning and manipulation of creatures known as "voidsent" from
beyond the corporeal realm.

A report by the scholars of the Nominated Observers of Artifacts Historical defines the "void" as "An otherworld parallel to the one in which man dwells. Abnormal events can weaken the veil between worlds, tearing it asunder and allowing the voidsent to invade the material realm. These fiends have a depraved appetite, and seek our world merely to consume the aether it contains, allowing neither beast nor man to stand in their way."

The mages of the Allagan Empire had previously experimented in forging covenants with the demons of the void in hopes of harnessing the creatures' powers. The Mhachi expanded on this endeavor, adding extra protections to their experiments so as not to invite the same fate that befell the Allagans.

To this end, the mages developed an occult device—the Nullstone—to preserve themselves and their city should a pact be broken. If a summoned voidsent refused to obey the master, a voidmage could smite the feral being using the Nullstone to sever its ties to the corporeal realm. It was in mastering this power that Mhachi came to believe in their civilization's supremacy over all others, eventually driving them to war.

As you can tell from the story arc, arrogance was as much to blame for the downfall of Mhach as it was the downfall of Allag. They took for granted that their protections and bindings and barriers were sufficient, but the techniques they learned from voidsent were deliberately flawed, destined to break down under certain eventual circumstances.