First time poster here.
I haven't looked through this whole thread yet - I got here by Googling "dark heresy haarlock komus phaenonites" (which should give you a few clues as to what I'm planning on throwing at my Acolytes) and landed on page 20. I've read up til this point (which was highly fascinating and useful) and something has struck me - I don't recall seeing any direct references to the Servants of Twilight (DotDG pages 11-13) even though that section has been referred to frequently. I point this out because a group apparently devoted to bringing about the Propheticum Hereticus Tenebrae would surely be immensely important to any theory regarding the Tyrant Star and whoever it is that is causing and/or exploiting it.
I will concede that I don't have any of the Haarlock's Legacy books (though I soon will), and don't know if they turn up there and for some reason haven't bee mentioned, or if they have already been discussed in the thread, but then, there have already been recurring points. Am I missing something?
Anyway, I'm also curious about what people have decided to do with the Servants, if anything. I personally intend them to be the 'big bads' of my campaign. Who they are is not set in stone - I definitely want a Phaenoninte leader (I've conceived of the name Alexandrus), Solkarn Senk of the Beast House (who in my campaign is an Eldar Pathfinder who fell to the Path of Damnation) and a senior Inquisitor of the Calixis Conclave (perhaps Zerbe himself).
I intend at least one of them to be the Unknown Heretic, possessing an as-yet unnamed ancient xeno-tech device to partially mask their souls in the warp, preventing their identity/ies to be divined. Alexandrus' and particularly Zerbe's motive for murdering Inquisitors would be quite simple: to remove any Inquisitor who should stumble upon their plans and failed conversions. Senk, meanwhile, loves to hunt, and there is little more varied and potentially dangerous prey than Inquisitors; he also has to wear such a device at all times to prevent his soul from being taken by She Who Thirsts, or from his former Craftworld (perhaps Ulthwé) from finding him. Senk's motive for making sure Erasmus Haarlock returns is also quite simple - what more could a hunter and enslaver of beasts want than for there to "be no difference between man and the beast"? I'm just throwing these ideas out to get a feel for what people think of them.