Supervike - your mention of the Dark Horse graphic novel put me in mind of a novel by Jake Arnott, 'House Of Rumour'. It's in part concerned with Rudolph Hess's flight to Scotland in 1941 & whether it was provoked by the actions of occultists (including Crowley, who features in the novel) influencing him through the astrological readings he (seemed to) give weight to.
It's a pretty good novel, (though don't expect pulp levels of action, it's more of a thoughtful read) which I certainly enjoyed, here's the inside cover blurb:
"Larry Zagorski spins wild tales of fantasy worlds for pulp magazines. But as the Second World War hangs in the balance, the lines between imagination and reality are starting to blur.
In London, spymasters enlist occultists in the war of propaganda. In Southern California, a charismatic rocket scientist summons dark forces and an SF writer founds a new religion. In Munich, Nazis consult astrologists as they plot peace with the West and dominion over the East. And a conspiracy is born that will ripple through the decades to come.
The truth, it seems, is stranger than anything Larry could invent. But when he looks back on the 20th century, the past is as uncertain as the future. Just where does truth end and illusion begin?"