Powers Usage

By Calgor Grim, in Deathwatch Rules Questions

Posted at

Ok so one of my players has raised an interesting question about the use of psychic powers and I'm a little bit undecided on this one. Now they do frequent here and they know who they are so if I spot you on here I know if you're dropping hints and trying to disrupt the conversation and I will drop rocks on you next session, big rocks that go boom! :)

A question has been asked concerning the uses of Compel and Machine Curse against Tau and their possible effectiveness.

My thoughts so far is that Compel may be partially useless on many Xenos races as you are asking them a command in Gothic while they might only understand Tau and therefore would have zero effectiveness. The other argument is whether you could target the pilot of a suit and force them to eject. My thoughts are whether the suit design would shield the user somewhat from the effect as in theory whats to stop you just using them to incapacitate an entire group of them or say using the idea on enemy tank units and asking them to stop the engine. The Machine trait would have allowed me a blanket no but it's not on a crisis suit and nothing says they need a direct line of sight on the pilot.

The other argument is over machine curse and whether that can be used to knock out a suit. It does state it can take out vehicles or weapons but the question is whether Imperial jinxing and understanding of how to jinx their own kit is still valid against alien technology. Also I would have guessed unlike many Imperial pieces, would Tau kit have internal failsafes. I would have said no and that isn't because it will break my entire campaign and give them an easy way to take out 90% of my adversaries. I could just use GM block but that would be mean and if I can get a better justification then that would be idea.

Other question, totally unrelated but it has me thinking it at the same time, would this same tech jinxing work on other alien tech such as Eldar Wraithbone and vehicles or Necron tech? That power is exceptionally vague and a really badly worded one.

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Eldar tech should be way out. The stuff is a psychic creation anyway, hardly even a machine as we understand it.

Necron tech fixes itself so fast even if you do break it, probably wouldn't hold for a few seconds. Most setting human tech is by fluff *tangentially* based on Necron tech and a human can read a Necron system if he's allowed so it's a meh there.

Ork tech? Who the @#$% knows. It only works because the orks THINK it does. If the orks see your psyker break enough human tech with his brain bullets, their stuff might just break even if he screws up the test because he wiggled his fingers at it!

Tau tech seems very much like human tech in most regards. While mechanicus magi can't quite figure out how they're handling some overheating issues the basic systems are well understood, only heretical because they don't come from a STC. Shutting down a suit, however, doesn't mean that you can actually get at the guy in it before he gets it running again. Also the second your psyker starts shutting down their battlesuits, guess who becomes Mr. #1 of @#$% kill that.

Just my 2c

Posted at
In my opinion, rules such as these should depend on your interpretation of the background. As such, I'm not sure there can be one single "right" answer to this, rather than a number of useful suggestions.


Technically, the RAW is clear on the subject. It does not specify these limitations as being part of the abilities you mentioned, so by the book they would not apply.


For Compel, it could be argued that the psyker does not actually transmit mere words but rather feelings and urges that do not require a language to bridge. Indeed, given how many dialects there are in the Imperium, this power might otherwise be fairly useless. Do note, however, that the rulebook also recommends a +20 modifier to the target's Willpower if the command is suicidal, which might apply to ejecting from a relatively save armoured suit right into a warzone. Personally, I'd reduce the modifier to a +10 compromise, taking into account that ejection is actually a safety feature (perhaps the psyker makes the target believe there is something wrong with their suit, triggering a sort of escape reflex).


With Machine Curse, it is nearly the same, in that here too the rules do not differentiate between the tech's origin. It is ironic that the effect would be easier to explain for Techmarines, given how Dark Heresy and its sister games seem to treat the Machine Spirit as actual Space Magic compared to mere superstition in GW's own d100 rules, but perhaps you could still think of the Librarian either having studied the tech in question (they are not called Librari ans for nothing), knowing its weaknesses, or alternatively that all the technology we see in 40k is quite simply similarly vulnerable to however this ability works (focused energy drain? power overload?). I'd say if, in your game, you'd have an EMP or Haywire grenade work against a machine or vehicle, then Machine Curse should work against it as well, fluffed as working on the same principles.


Either way, the book's ruling seems pretty clear to me. If, however, your group consensus does not agree with either of these things from a background PoV, then feel free to change the rules to have them conform to your version of the setting. This is one of the primary advantages of playing a P&P, and I could easily see reasons to apply this level of freedom here. :)

Edited by Lynata
Posted at

Interesting thoughts, I do also recall that Eldar tech being psychicaly reactive and wraithbone should be very hard to knock out but it's RAW element which means that theoretically it could apply and all I can do is use a GM block on most things.

Ork tech, it breaks anyway when in a non ork hand. Also the Ork will probably just not notice, say "DAKKA DAKKA DAKKA" while its trying to fire and yet still it will somehow work.

So far my safest block is either give suits the Machine Trait equivalent to their armour value and use that instead of armour or shields. Forcefields can block all psychic powers.

I'm happy to use home brew but I would like to see if anyone else has encountered it and how they have resolved it first. No point reinventing the wheel.

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Similar to the warp weapon vs tanks question. Either you consider the vehicle shielded or you don't. Fluff supports it. Rules are quiet on it.

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Well the compromise I'm working on for Machine Curse is something about the relative size of the object and the casters Psy Rating. A quick scribble:

PR 1 - 3

May mess around with various pieces of tech such as weapons, chronos, hand held auspex etc. May disrupt things about as large as a Shield Drone.

PR 4 - 6

May target and mess with things up to small walkers and tanks.

PR 7 - 9

May disrupt main battle tanks, heavier craft and vehicles.

PR 10+

Titan territory and Superheavy vehicles.

Edited by Calgor Grim
Posted at

Sounds like a good compromise, though I would say you could also make it depend on the DoS. It is almost the same thing (seeing as PR influences DoS), but allows even lesser psykers success, or better psykers to fail, depending on how their power actually manifests as opposed to what they might be capable of.

Posted at

Sounds like a good compromise, though I would say you could also make it depend on the DoS. It is almost the same thing (seeing as PR influences DoS), but allows even lesser psykers success, or better psykers to fail, depending on how their power actually manifests as opposed to what they might be capable of.

Threshold using additive of DoS and PR then? A lesser psyker should really be limited though, with the greatest will in the world even an Iota level psyker (going on the assignment scale) should not be able to really have any chance of manipulating the complex tech on a main battle tank but could probably mess with a few guns even if he did have a shedload of Willpower. Gah, so many numbers to think of.

The player's primary concern is they don't want to pick up the power to mess with machines and have me as a GM say "No you can't use it" and block him. But I also don't want him to use it and make a laughing stock of some of my best elites/master tier enemies, disabling them so a squad can wail on them for the next few rounds and it's unable to act so there needs to be a compromise of some description. Frankly in such a state if it did come into play my options are to stay out of range of it and then just make them a walking target to ensure they get dropped first or find some way of rebalancing the gaping hole that FFG left. There really is nothing in that power description to help and it effectively says that even the basic space marine with it can knock out a Super heavy Baneblade for a round leaving it sat there like a giant metallic terrain piece.

Posted at

Sounds like a good compromise, though I would say you could also make it depend on the DoS. It is almost the same thing (seeing as PR influences DoS), but allows even lesser psykers success, or better psykers to fail, depending on how their power actually manifests as opposed to what they might be capable of.

Or similarly, make it a penalty to the WP test based on size. This allows you to add granularity of warding that acts as a further penalty. Normal lemon russ -30, the commandant's personal LR -50.