Also known as, “Demonic Arts” by most people, it is the arcane school used by those who have either sold themselves to a elder daemon in order to learn the wicked arts; traded countless lives to a daemon for the knowledge; or lastly learned from someone who knew the art, and the likelihood of that is very little.
This school was supposedly ‘created’ or rather, discovered during the immortal wars first by the child king known as Hara’thro; Hara’thro was dubbed to be known as the King of Yeresse and founded a large band of Veneficae magi in order to attempt to unmake the world weave and recreate it in his own image... or perhaps that of another, the truth behind such is entirely unknown.
The art itself is known to originate from demons and is a art that can be assumed to come natural to some of them because of the methodology in it’s usage. If there is a negative effect beyond the initial prices on human beings for learning or using the art is unknown, but there are no known users that live at this time and it is assumed most were insane due to the very usage of the art being reckless.
What little is known about the true dark art of Veneficium is that rather than work with the weave it has a number of ways it will work; first the veneficae taints the weave by means unknown to ordinary men then use the now tainted and chaotic flowing weave to work their dark magicks, alternatively the Veneficae will tear the weave itself apart rendering most magi unable to even able to defend themselves magically; but less harm the dark magi.
This method is also rumored to make a cleric unable to reach their god’s within the tainted area of the weave, but it is known it was the holy arts channeled through the Eria that largely restored the damaged portions of the weave after the tragic immortal wars.
For now, it is assumed the dark art itself no longer is ever practiced among humanity; but perhaps eventually humans with dark enough hearts will slink out from the shadows to once again pursue the wicked practice.