**Emdief's thaumometer gave him a magic boost; he simply shoved all of it into disrupting other magic. My dwarf is just realizing that he never measured how strong the boost was.
I personally like to imagine that Emdief's high magic resistance was a result of divine intervention, and that he/she/it is being used by Armok as an assassin. After all, he/she/it is being granted passage to and from the afterlife on a repeated basis, and I prefer to think there's some overlying plan about that rather than a series of coincidences. Not to mention Emdief does at one point carry a message from Armok to Oku, although its during their final confrontation. I imagine Emdief's knowledge of he/she/its purpose is rather hazy.
This theory (your theory, and I think 4mask also had a theory at some point about the nature of Emdief's resistance) makes events at Steelhold even more confusing and ominous. What exactly was it Oku was doing that would justify such extreme intervention in mortal affairs? Armok generally doesn't do squat to save his creations. Oku and her 'True Gods' are confirmed to be hated by Armok to the extreme, to the point that he gives people otherwise condemned to hell mere purgatory if they even opposed them in spirit.
I feel like the Fall of Steelhold was the metaphorical visible tip of the iceberg in a much greater conflict, one carried out beyond mortal comprehension. Some potential other instances in this conflict can be seen;
-An earlier demonic breach occured at some point (with Moisturizer) but it was covered up by the Queen.
-High-ranking dwarves in the kingdom funded and sanctioned an attempt to replace dwarven body parts (even parts of the mind, although that was doomed to get precisely nowhere) but where killed when discovered. It could have been because the Queen dissaproved... or it could be due to their carelessness and general incompetence putting an overall objective at risk.
-The Queen was later confirmed by Rhaken to have conspired with vampires (and, somehow, with cyclops) to murder her way to the throne. Also, cyclops repeatedly attacked Steelhold. Vampires are generally enemies of the Old Gods, although they are responsible for their creation.
-If Oku is taken as a trustworthy source (the
Codex Arcana is amazing, by the way. I hope 4mask keeps it up) the Demons were the children of the True Gods, cursed with insanity. Emdief later states that Armok did
something to the demons.
-A mine was flooded with magma for no discernable reason. Firecrazy may have been framed, or (as he later becomes a flaming berserker for no apparent reason) something else might have pushed him into it. I like to think this was actually Armok/the Old Gods preventing another attempted breach.
Basically, I think that Steelhold wasn't just a fortress; it was a battleground between gods Old and True. Almost all the characters we saw were unwittingly (for most of them; some were wittingly) manipulated into a hellbreach. However, I don't think everything went according to plan. If the Bloodkin were purposefully created for the purpose of killing Armok's children (probably to avenge the loss of the demons), they aren't precisely what the True Gods intended. This would be because precisely nobody reckoned on Corley; although apparently at odds with the other progenitors of the Bloodkin, he really struck me as a self-serving, chaotic and unplanned actor. How much Corley's influence messed up the Bloodkin, I cannot say, but I suspect that his interference/the successful repression of the cult at least means that the Bloodkin are not active worshippers of the true gods.
Appologies for long post, I love me some lore theorizing.
EDIT: @Asmoth: Vlad
could be a sociopath, but in the style of real life sociopaths rather than Hollywood style. As in he doesn't have a complete lack of emotion, but is rather typically emotional. And has a reduced rather than completely absent capacity to experience empathy.
Sociopaths IRL are capable of having true friendships and even romantic feelings, at least in minor cases. They are mostly characterized by reduced capacity for empathy and guilt. To put this in perspective, some estimates state that 1 in 100 people is a functional sociopath, meaning you've probably met a few and don't know it. 2spooky.
So, I'd say he genuinely cares for his friends, Thane and the members of the militia, although in the later case it might be because even if he doesn't empathize with them personally he knows what it's like to be on the receiving end of terribly thought out orders. But I do know this, although it hasn't been made obvious on purpose; Vlad is carefully maintaining a facade to mask his true thoughts and motivations. This is why he goes from being a somewhat silly, harsh pragmatist with a heart o' gold to a serious and ruthless tactician at times.