About halfway through the second book, I thought of taking up a few notes from the stories. The first one had comparatively little of immediate interest, so I won't be going back to it, but in the second I found a number of things. Still, this isn't some exhaustive analysis of the whole novel I'm posting. Consider, rather, the following a selection of highlights that caught my attention.
Space Wolves Omnibus p. 276-77 wrote:Ragnar raised his [bolt] pistol and sent a bullet through one of the ogryn's eyes. Still it did not fall, but reached out for him with its remaining good hand. Was the creature simply too stupid to die, Ragnar wondered, or was some dark sorcery at work here?
[…]
Yet for a moment he had another clear shot at the monster, so he put a bullet through its other eye, convinced that blinding it at least would give him all the advantage he would need in the coming fight. It was more than enough. This time the bullet passed clean through the abhuman's thick skull and blew its few brains over the wall of the chamber.
For whoever doesn't know, ogryns are basically the 40k equivalent of ogres -- huge mutants who are maybe two to three or so meters tall but otherwise not very magical creatures. (This particular example is also suffering some debilitating disease due to Chaos corruption.) Ragnar needs multiple headshots at point blank range with his bolt pistol to put it out of action.
Ragnar, young and somewhat simple Space Wolf marine is talking to an inquisitor named Karah Isaan. If we are to trust the lady inquisitor's words, inquisition information management sounds substantially inferior to what we would expect of a moderately competent modern-day intelligence agency.p. 315 wrote:"There are gaps in the records of your auto-librams."
Ragnar was not familiar with the term, but it sounded like she was referring to the Thinking Engines. He nodded thoughtfully.
"It is the same with us," she continued. "The machines are old, dating from the Dark Age of Technology, and their systems have been reconsecrated many times by the tech-priests of the Adeptus Mechanicus. Each time that happens, information is lost. There are flaws in the copying process. And, of course, much information is recorded under the individual seal of a specific inquisitor - - and sometimes those seals are lost when the inquisitor dies and no one can then access his records."
Details on the capabilities of a psyker. As in many settings, willpower appears to be a criterion for successfully resisting psi-powers.p. 317 wrote:"You are a psyker. Why do you not simply lift the knowledge you need from other people's minds?"
She smiled again, this time coldly, as if this was a subject she did not care to discuss. "Some psykers have that gift, but not I, my talents run in... other directions. Even for those with the gift it is not that simple. A strong-willed individual can resist them. More subtle ones can mask their thoughts or even send false thoughts. And there are other risks..."
"Risks?"
"Yes. Those who enter the minds of heretics often become heretics in turn. Their very thoughts are a contagion."
Assuming a somewhat short active life of forty years we obtain from this a figure on the order of fifteen million worlds in the galaxy. This appears, then, to indicate the Imperium of Man contains only a rather small fraction of the planets in the galaxy inhabited by humans, if Ragnar's source is to be trusted. Further, Ragnar believes there are "millions" of worlds in the Imperium, plural, which would seem to be in conflict with numerous sources pegging the Imperium at 1 million planets or thereabouts.p. 330 wrote:It was only one world but there were millions of such worlds in the Imperium, separated by thousands of light years of distance. He [Ragnar] had heard it said that if a man could visit one new world in the galaxy every day of his life, he would not have visited a thousandth of the inhabited worlds by the time he died.
An IoM warship of the Inquisition. Not much detail is given, though we can safely conclude its dimensions most likely exceed 1 km by a considerable margin.p. 332-33 wrote:The thing was a flying mountain, a huge wedge of steel and ceramite which dwarfed the Thunderhawk the way a whale might dwarf a minnow. As they neared it, the Space Wolf could see that it bristled with enormous weapons. Huge turrets and emplacements bulged in its side. The Imperial eagle painted on its meteor-pitted flanks was almost a thousand strides across. Beneath it, in Imperial Gothic script, were painted the words Light of Truth. Ragnar guessed it was the ship's name.
Teleporters are very rare and unreliable technology. Even for an inquisitor's vessel and for Space Marines, both very "elite" groups in the Imperium, they aren't anything like standard.p. 339 wrote:Sternberg had claimed there was a teleporter on his ship. If that was true, it was a sign of the regard the inquisitor was held in. Such devices were as rare and precious as they were temperamental. Only the Terminator companies of the Space Marine Chapters used them, and then only during missions of utmost urgency and importance. The mystical ancient devices allowed small groups and cargoes to be shifted between themselves and other areas without crossing intervening space, or so the knowledge placed inside Ragnar's head told him.
This illustrates the generally dangerous and unreliable nature of warp travel. Examples are given of extreme outcomes for those brave enough to risk travel through it.p. 350-51 wrote:The warp itself was a turbulent medium, unstable, as full of ebbs and flows as a mighty ocean. It was said to be haunted by daemons and ghosts and the hulks of the thousands of ships, some of them human, which had been lost in it since time immemorial. It was a shifting, ill-understood realm which filled even those who travelled through it with superstitious dread. All manner of tales were told about the warp. Of starsailors who travelled through it convinced that only days had passed and who later emerged to find centuries had gone by in real time and that all who knew them were dead and gone. It had happened even to the Space Wolves. Ships had been deemed lost for hundreds of years and then their crews had returned to the Fang, unheralded and unexpected, to rejoin their comrades. And other, stranger fates had befallen travellers as well. Sometimes crews would travel out and return what seemed days later to their comrades; only when they emerged from their ships, they had grown old and senile and some had died of ageing. Their crews felt like they had been lost for decades in the warp, and showed all the effects of having been so. Sometimes entire crews went insane the moment they slipped into the Immaterium. No one knew why. And sometimes, most ominously of all, ships, even entire fleets vanished, never to be seen or heard from again. It was all down to luck, the favour of the Emperor and the skill of the Navigator.
Ragnar and the lady inquisitor again. Space Marines can take multiple penetrating bolter impacts in the head and chest and survive, though Ragnar was badly wounded in the incident and out of it for some time afterward.p. 436 wrote:"I meant: how did I come to be here? Was I wounded?"
"In several places. We had to dig bolter shells out of your chest and your head."
Here there appears to be a single "million worlds of the faithful" in the Imperium. This would seem to fit better with the more established figure than Ragnar's "millions" from earlier.p. 446 wrote:It occurred to him, for the first time, just how vast and variegated the Imperium was. Each of the great departments of the Ecclesiarchy was a world unto itself, with its own rules, codes, and functions. They stood apart from each other as well as the mass of humanity they ruled in the Emperor's name. It was only the core of shared faith that bound them, and the million worlds of the faithful.
Description of Aerius, an exceptionally populous and productive Hive planet.p.481 wrote:Aerius was a smaller world than Fenris, that much was obvious, and the surface of its landmasses glittered darkly in the sun's light. As the shuttle drove downwards into the atmosphere he realised exactly why. The entire surface of the continent at which they were aimed was sheathed in metal. The whole surface was one huge industrial city. The black clouds that obscured the sky below them were not natural, but the products of enormous factories. Chimneys as large as mountains spewed chemical pollutants into die sky. Here and there he could see monstrous burning pits that looked like lakes of molten lava. He guessed, from the knowledge placed in his brain by the tutelary engines, that these were the waste products of the titanic factories for which Aerius was famous.
Supposedly a trillion souls live on the planet, though this is only a vague estimate with large uncertainties. Out of universe, Aerius probably gets the single highest population number I know of for 40k planets. This fits well with its exceptional nature as otherwise noted.p. 482 wrote:"It is said that a million, million people lived on Aerius." Inquisitor Sternberg said. He had obviously overheard Ragnar's question. "No one knows for sure. The Ecclesiarchy have never been able to get more than a small percentage of them on the census rolls."
"It must be a very bountiful world." Ragnar said.
"Bountiful and terrible." Sternberg replied. "It is one of the most productive Hive Worlds in the Imperium. Its manufactories supply over half the worlds of this sector. If it were lost it would be a terrible blow to the Imperium."