In the time of magic, before the Great Purge, there were a rare and powerful class of vorbright called soulpiercers. While typical sorcerers could harness magical energy to then use in a number of ways, only the soulpiercer could harness magic that was already inside another spellcaster, essentially giving them full control over the subject. Acquiring command of a subject outside oneself was possible, such as in the case of animals, but there was always a payoff in that magic collection and expenditure was always required; one needed a reserve that far exceeded the fex contained within the target to succeed. With soulpiercers, this was not the case. They could use fex that was contained in another without needing the excess reserve.
These mages were so dangerous that eventually all schools of magic would kill off any students that showed any signs of having these abilities. These special individuals would only appear once every few generations.
Present Day
Niril the Arkaeni, whose expertise lies in ancient religion and magic, took an interest in the so-called magical properties contained within the drug adoxipham, which he came to believe was made using the blood of living Vurg. Through his research and with the help of Doctor Talmage, they were able to produce a synthetic hormone called phyrocinin, which could replicate the effects of the ancient abilities possessed by these rare and powerful individuals. This eventually won favor with the Emperor, who continued to fund Niril's research into adoxipham and the Vurg.