What would be a good group of Acolytes who serve an Ordo Xenos Inquisitor of the Thorian philosophy?
Retinue of a Thorian Ordo Xenos Inquisitor.
"Thorian Inquisitors often recruit those with a keen eye for investigation into their cadres. Sages able to research every branch of a family tree going back millennia, and Enforcers with their talent from the hunt are both useful allies" ( Ascension 162). The "family tree going back millennia" part doesn't really apply to Ordo Xenos, but the rest still fits your Inquisitor. Basically, then, you're generally looking at Adepts and Arbitrators (Scum and Tech-Priests too, but they're not as *perfect* a fit). More specifically, however, an Ordo Xenos Inquisitor is going to be looking for those Careers focused on Xenos. To that end, here is my list of Alternate Ranks whose mechanics fit with a Thorian Ordo Xenos Inquisitor even if the fluff doesn't.
In order of increasing radical-ness:
Verispex Adept (BoJ 54-55)
Feral Warrior (IH 62-63)
Calixian Xeno-arcanist (IH 58-59)
Cult Stalker (DH 50-51)
Calixian Malatek - The Power Without (TLW 36-38)
Verispex, Xeno-arcanist, and Malatek (and Stalker, see next sentence) cover investigation and research extremely well while Warrior gives the team muscle and experience in combatting xenos. I would play the Stalker more towards his "shady past, connections with non-Imperials, interpersonal" side (so probably Scum); certainly if it were an Arbiter then s/he would add to the investigative power of the group.
For more information on the Thorian philosophy, the GW website has a 33 page "sourcebook" for the game Inquisitor available to download. Obviously the mechanics don't translate but the fluff is gold (minus the grammar and spelling of course). The section on Thorians in the Ordo Xenos would be of particular interest to a GM looking for ideas.
Aforementioned PDF can be found here - it's the Thorian Sourcebook.
It also features some more suggestions for a Thorian Inquisitor's cadre:
As far as warrior bands go, Thorians are also pretty versatile. Their particular and peculiar relationship with the Ecclesiarchy, and their focus on the Emperor, means that they attract more Ministorum adepts and warriors than other Inquisitors. A good start are the Cultists and Fanatics characters discussed in "Inquisitor", to represent resurrectionist sects and individuals within the Ministorum. Such individuals will be only too eager to help a Thorian Inquisitor, although their somewhat unpredictable behaviour can also prove to be a problem for their master.
The "Inquisitor" book also contains sample characters from the clergy of the Ministorum, and a Preacher, Drill Abbot, or Cardinal may well find themselves inducted into the retinue of a Thorian, either temporarily or on a permanent basis. The companionship of these individuals is often a great comfort for the Inquisitor, and their connections within the Ecclesiarchy and ability to interact with the unwashed masses of humanity can make them valuable aides as well as warriors.
Similarly, a Thorian connected with the Ecclesiarchy may well be able to procure himself an Arco-flagellant or two. Not only are these berserk warriors useful to have around in a crisis, but the tortuous alterations visited upon their bodies can also provide a Thorian Inquisitor with a useful subject for investigations into the nature of a Divine Vessel.
In short, dismissing specific Alternate Ranks in favour of classes and general concepts, I'd suggest a Cleric for the Ministorum-touch and an Adept to catalogue all the important details of investigation (both related to the Inquisitor's temporary investigation as well as their ongoing mission regarding the Emperor's divine guidance), and for muscle perhaps a Guardsman (representing either a faithful Veteran Guardsman or a Frateris Militia cultist?), maybe a Scum as a sort of specialist (Xenos bounty hunter?). Arbites might work as well, as they have been raised in the Schola Progenium and would thus be very faithful to the Imperial Creed.
Edited
by Lynata
Hey guys, thank you for this information, but I have another question. How would a Psyker fit into the retinue?
All branches of the imperium rely on psykers and importantly the emperor is a psyker himself so any more permanent vessel would also need to be. A telepath or biomancer would be able to provide a valuable and otherwise inaccessible insight into the psychic condition both in general and of any potential vessel of divine manifestation.
'Thorian' is very much an 'overall goal' - if he's Ordo Xenos, his 'day-to-day job' is protecting the Imperium from Xenos influence and corruption. At the same time, gaining an understanding of Xenos technology or psychic techniques relevant to Thorian goals is an important side benefit - so Tech-Priests and Psyker-Scholars which would assist him in doing this would be useful - and at the same time be useful in their investigative role; I can imagine him having a focus on certain Cold Trade merchandise, things like Halo Devices which can supposedly resurrect their users from death.