Okay I admit sometimes I like to incorporate aspects of other games that I probably won't get to run but enjoy greatly. One such game is CthulhuTech. Anyway, the Tagers and Dhohanoids are monsters from the beyond that graft to the human soul granting them tremendous power and the ability to shift either parts of their body or their entire form. Tagers are the Holy Warriors that help to defend Humanity from the Old Golds and their mortal thralls. The Dhohanoids are vile monsters that are agents of the Old Gods that seeks to cause Humanity to bend its knee to the old ones.
Now for the Tagers and the Eldritch Society could be an organization of radical inquisitors and other humans including Rogue Traders in a large sector spanning corporation. Not everything in the Warp is twisted and perverted. The Eldar gods existed within the Warp and sufficient belief is enough to create such entities. It is to these entities that humanity calls to them. Few of them are pretty but they are immensely strong and gifted in ways no human could ever hope to be. Acting in complete and utter secrecy none can know they exist or the Imperium would turn on one of the greatest weapons they have against the coming tide. The Dhohanoids and the Chrysalis Corporation would be a front for the Dark Mechanicum or even the Q'sal Magisters. Binding daemonic entities more fully and completely into a human host making them impossible to separate.
The other idea I had is they were vat grown symbiotic organisms that granted their hosts tremendous power but the continual erosion of their sanity and corruption as such inhuman things weigh on their minds and souls. Has anyone else ever used these before?