I designed the book as a narrative history that incorporates and unifies the many legends of the Nazi occult, building it up by layers from over sixty different sources, many of them summarizing or recapitulating further works of widely ranging reliability and sanity. Plus lots and lots of Google Translate.
I began with the absolute substrate of real, provable Nazi involvement with the occult, as found in the works of Real Historians (tm) like Michael Kater, Heather Pringle, Hans Thomas Hakl, and the late great Nicholas Goodrick-Clarke. Everything I found out about the real Nazi occult is in the book. I left nothing out.
Then onto that, I layered information from generally reliable or well-researched books by occultists or researchers of the fringe, such as Ellic Howe, Nick Cook, Joscelyn Godwin, and (believe it or not) Peter Levenda.
Then I piled up nonsense, uncritically seined or imagined by conspiracy theorists and goofballs like Trevor Ravenscroft, Peter Moon, and whoever it is that has that giant website on Maria Orsic and the Nazi connection to Aldebaran. (Which now seems to be down. Of course it is.)
Then I added a soupcon of relevant shout-outs to the relevant fiction. Sharp-eyed Hellboy fans will notice a thing or two, for example.
Then I made up enough material to fill in the blanks, reconcile the many contradictions, and create a convincing-seeming narrative history, including almost all of the specifics of the "Hexensoldat" unit, Sonderverband Z.
Perhaps the best way to explain it is to show it done. Osprey has put up an excerpt from the book here, complete with Darren Tan's terrific illustration of my tribute to the "three guys standing there" subgenre of Osprey art. (The three guys in the illo are an Ahnenerbe archaeologist, an Ahnenerbe-SS rune magician, and a Hexensoldat of Sonderverband Z.) The excerpt deals with the Marineforschungsabteilung (Naval Research Institute; MFA). Herewith, I shall Nevins myself:
Admiral Canaris established the Marineforschungsabteilung (Naval Research Institute; MFA) as a secret office of the Abwehr devoted to unconventional reconnaissance methodology. Its initial missions were theft of British radar and sonar secrets, and the deployment of concealed weather stations in the North Atlantic.
This is all true, including the secret weather stations.
Headed by Otto Friedrich Muck (who invented the snorkel in 1942), MFA employed a number of Thulist mystics as part of its general concern with Arctic matters, but did not prioritize occult researches until a series of events in 1938 surfaced coincidentally.
It was not headed by Muck, although he was involved with the real MFA. I picked him because after the war he became a major proponent of Atlantis theory. I don't know that it involved Thulist mystics, but it made sense that it might. They got everywhere.
The first was a March 1938 contact with the astronomer and astrologer Wilhelm Hartmann of Nuremberg Observatory, a member of the Vril-Gesellschaft who demonstrated the possibility of harnessing comets by electrical force.
Hartmann is real; he really believed that, but he had no contact with MFA. (That I know of.) The Vril-Gesellschaft never existed, at least under that name, but has gained currency thanks to Willy Ley's article describing real Nazi interest in the (fictional) vril-force. There was at least one esoteric publishing group in Nazi Germany dedicated to publishing vril secrets. I mention it by name in the book.
Then in May came the report of Untersturmführer Paul Birkert, who had led a meteorological and geological expedition to Greenland in August 1937 after the Ahnenerbe rejected his proposal. He described Eskimo angakoks who could accurately describe conditions in the South Pacific in their dreams, and he returned with artifacts taken from fortress walls crushed by glacial ice -- relics of Thule itself. These relics matched material from the Von Lorfmon expedition to the Cape Verde Islands in 1912, and from the wreckage of U-29, lost in 1917 and salvaged by an expedition to the Azores in October 1938. These three widely separated finds convinced Muck of Thule's reality.
Birkert is real, and really went to Greenland after being rejected by the Ahnenerbe. The Eskimo angakoks are taken, of course, from Lovecraft's "Call of Cthulhu." The Von Lorfmon expedition is from Robert E. Howard's Atlantean-Yellow-Menace novel Skull-Face. The U-29 is from Lovecraft's story "The Temple." The expedition to the Azores is based on the International Gulf Stream Expedition in 1938, headed by the oceanographer Georg Wüst, whose soundings on that and a previous expedition convinced Muck in real life that Atlantis existed.
In 1940 after the fall of Norway, the MFA pushed for a sorcerous and meteorological station on Spitsbergen, another likely Thule remnant in the Arctic. In September 1943, just such a team landed on Hopen Island under cover of Operation Zitronella; it included at least one Hexensoldat, a veteran of the Navy's Brandenburger special forces.
Real: MFA, Brandenburgers, Spitsbergen, Operation Zitronella, meteorological station therein. Occult: Thule connection. My imagination: "one Hexensoldat."
During the battle of the Atlantic, the MFA (now commanded by Fregattenkapitän Hans A. Roeder) kept a house full of pendulum dowsers and astrologers in Admiral-von-Schroeder-Strasse, near Abwehr headquarters. By swinging a special pendulum of Thule material over a map of the Atlantic, a trained dowser could locate Allied shipping. The seers (such as the Tarot-diviner A.F. Glahn) who used the techniques derived from the Greenland Eskimo shamans had a much higher success rate, but died or went insane at an alarming rate. The Pendulum-Institut's star diviner, the elderly Ludwig Straniak, nearly died of a stroke during the cruise of the Bismarck. In 1943, Roeder moved the Pendulum-Institut to the island of Sylt off Schleswig-Holstein, likely to keep his astrologers out of the clutches of the SS.
Almost all of this paragraph comes to us from the memoirs of Wilhelm Wulff, Himmler's astrologer. Roeder is real, as is the address. Pendulum-magician Straniak was real. He really did nearly die of overwork as noted. Tarot-diviner Glahn is real, he was also a pendulum-dowser, and he really did die in 1941. I added the "Thule material" to the pendulum, but the rest is as Wulff told it. Those Greenland Eskimo techniques are, again, my extrapolation from Lovecraft.
In September 1942, Canaris moved the MFA from the Abwehr to a billet under the larger Kriegsmarine Amtsgruppe Forschung, Erfindungs- und Patentwesen (Navy Office Group Research, Inventions, and Patents; FEP), possibly to disguise it from bureaucratic SS poaching. This proved prescient when Ernst Kaltenbrunner purged Canaris' Abwehr completely after July 1944.
And this is just real history. Ta-daaa!