After long service across the galaxy, Rex rapidly advanced within the Inquisition's ranks to become a valued servant of the inner circle of the Ordo Malleus, privy to highly restricted information about the true nature of daemons and how they were to be combated. Rex rose to become the Proctor-General of the Scarus Conclave which oversaw all Inquisitorial affairs in the Scarus Sector of the Segmentum Obscurus, with many other Inquisitors and Acolytes as his servants. He possessed almost unlimited powers with which to deal with any Chaotic threat in the sector.