Necrons are robotic bodies with the minds of formerly living beings downloaded into them; so, do they have 'souls' that make them psychicly detectable? Or is the 'mind' they contain just a digitized 'copy' of the original that has no psychic signature?

Read the manual, mate. BC core rulebook, p 107: "Psyniscience (perception) Those with the psyniscience skill sense the currents and eddies of the Warp and Immaterium. Characters can use the skill to detect the presence or absence of daemons, or use of psychic powers, or psychic phenomena, disturbances, or areas where the flow of the Immaterium has been unsettled or disrupted. …"

Rules as written, you can't even detect a human psyker with this power unless he's actually manifesting an ability. (It says use of psychic powers.) So, there is no reason for a soulless Necron to register; they have a distinct lack of psychic powers. The only Necron device that should register to psyniscience is the null field matrices they use to protect some of their tomb-worlds, as those ward against the Immaterium and are known to disrupt both psychic powers and daemonic manifestations.

Cheers,

- V.

psyniscience by itself, more than likely not. but iirc, there is a psychic power that allows you to detect people in a very general way. or maybe thats in dark heresy… dang it, now i have to get home and look.

so i guess a follow up question would be (if the psychic ability is indeed black crusade, not dark heresy): can you use psychic powers to detect necrons seeing as how they arent really people anymore?

Oops- I was conflating Psyniscience with Sense Presence from DH , which detects life-forms (I posted the question in the BC Forums because BC has the official stats for basic Necrons). My bad. I usually post on the Forums on my way home from work, so I'm usually a little burnt out…

More generally speaking, do psi powers that specifically effect living things or influence/detect minds/souls work on Necrons, or does their Machine Trait trump all? Are they ultimately considered 'robots', or living minds 'wearing' robot bodies?

I'd say their immune, seeing as how anyone with the Machine Trait, from Servitors (organic brains with cybernetic bits) to the Heretek with Mechanicus Assimilation, are. A digitally stored consciousness seems a lot more robots than those.

That said, sensing them with psychic powers depends entirely on how you reason said powers work. If it's sensing souls, then probably not. If it's sensing physical presences, then certainly. if it's both, yeah, sure. If it's something else, well, look to common sense and rule of fun to guide you!

As far as other powers go, I'd say that powers that are specifically about living tissue/beings, such as biokinesis (Forbidden Lore is an excellent unofficial supplement even in it's unfinished state!) then yeah, Necrons ain't gonna suffer much. That said, the warp is a strange and wicked thing, and I'd say things not explicitly flesh only (such as Gift of Chaos, Leper's Curse and Bolt of Change) might very well work their twisted magic anyway, as the GM reasons.