I'm thinking of employing Gue'silva (Human members of the Tau Empire left behind from the Damocles Crusade) Psykers against members of the Deathwatch. I'd like to stick as close to the general background material on Gue'silva/Gue'vesa as much as possible. The problem with that is that I haven't been able to find any information on how the Tau handle Psyker's, much less client race Psykers. Does anyone have a references to Tau Psyker policy? I have the 3rd edition Codex and Imperial Armour Volume Three, but they don't reference Tau and pyskers at all.

My plan, is to use Gue'silva Pyskers similarly to Eldar Warlock i.e. in a squad support role. Essentially they would utilize variations of powers from Dark Heresy and Rogue Trader such as Inspiring Aura, White Noise, and Electrical Pulse to improve the Hordes they are attached to or hamper the PCs. While this isn't that all revolutionary and idea it may stray too far from the established background to be truly viable. Thoughts?

I'm pretty sure the type of material you are interested in doesn't exist. The original material on Gue'silva was based on the assumptions that the rank-and-file troops within several Imperial Guard regiments got left behind in middle of Tau territory and defected to Tau Empire. As common Imperial Guard troopers they didn't have any psykers within their ranks at all (save for perhaps a a single isolated case of Sanctioned Psyker being left behind with them). Thus the issue never came up and GW didn't write anything on it.

The good thing is that it means you are pretty much free to make whatever you want of it. Just remember that any psykers found or born to humans within Tau empire will have no-one to test them, no institution to train them and no-one to help them come to terms with their power safely. In essence they are 'wild psykers' and unlike highly trained Sanctioned Psykers or Eldar Warlocks they would be prime material for daemonic corruption and possession with no way to protect themselves from it.... Which is not necessarily a BAD thing as it gives you perfect excuse to throw some chaos-corrupted, pulse-rifle wielding Tau lunatics with daemonhosts in Kill Teams path. Delicious.

I was pretty sure I was breaking new ground with the idea when I posted it. My understanding is that a more substantial amount of humans than just a few Imperial Guard regiments from the Damocles Crusade that came under the control of the Tau at the end of the Crusade. I agree that there would a be a distinct lack of formal human training methods and institutions available to Gue'silva and Gue'vesa. Hence my desire to know if anything was written about Tau psychic policy. Given that the Nicassar are a highly psychic client race/ally of the Tau it would be safe to assume that the Tau have developed some form of policy for dealing with Psykers among their client races. Since Gue'silva/'vesa lack an access to the Scholastica Psykana, all psychics would be culled by the Tau or more likely the Nicassar would oversee the development and culling of Gue'silva/vesa for the Tau. Mind that this is all extrapolation from the very sparse information available to me.

Polaria said:

That's pretty cool. From the tau perspective, humans probably seem to be horrifying in the extreme... a huge alien race, whose numbers are limitless, whose favorite activity is genocide, and who are a living conduit to the realm of daemons.

In a similar vein, I had a friend who converted some possessed Tau Battlesuits. The concept are was pretty cool, but he's not too good with greenstuff, so it didn't turn out the best. Props for effort though.

Oh, and it completely ignored the fluff, but I didn't tell him that

Lets say that the Tau figure out that untrained psykers are a bad thing*. Assuming that the Tau don't like the simple option of just killing psykers as they are found, and that the Nicassar can't or won't help with the problem, what are the other ways the Tau could deal with human psykers ?

The more convoluted the better. I'm sure that there are factions within the Imperium who would just love to be able to fly ships right up to Tau held worlds (to spy and transport "people trained in managing psykers" to and from the planet), even if that ship is one of the Black Ships.

*A couple of psykers summoning daemons should be enough to do it, especially when the Tau interrogate the people who were in charge of managing the worlds psykers, up until the Tau claimed that world.

@Bilateralrope

I'd imagine they would have to build a training institution from the ground up. Man would have to re-learn the lessons of the 24th millenium (I think that was when Psykers were scientifically acknowledged). It would be a LOT of painful trial by error. You would probably see an increase of Warp-related incidents which the Tau would counter with their superior technology and Nicassar support. I can't see the Nicassar NOT being involved as they are a client race and helping control and guide humans psykers would contribute to the Greater Good. Imperial access to Geu'vesa psykers whether through some form of Scholastica Psykana mission or the Black Ships would be a non-starter. After all psykers are a valuable resource for the Imperium, a fact which the Imperium does not like to admit but cannot ignore. Why would the Tau even give them indirect access to that resource?