
My own character made a Faustian deal with an Ahriman for power, hoping that it would help him gain the knowledge he needed to master the three primary forms of magic. He created a replica of the Necrologos under the guidance of the Ahriman (which he actually uses as his Grimoire), and while he believes he has the Voidsent bound to his will it's more or less the other way around. Hence the Faustian deal.