Runes of Doom (1978) finally ties up threads left dangling from the other two volumes. Thank goodness. It is probably my favorite of the Grimoire series. 

First off, we finally have rules for playing Phraints, humanoid insect warriors that are repeatedly mentioned as playable in the previous books, but without any indication as to how play them. I’d wouldn’t be surprised if you told me that they directly inspired D&D’s Thri-Kreen. 

Second, we finally get stats for the energy weapons used by the Techno class, which cements Arduin’s commitment to a strong flavoring of science fantasy, two years before Expedition to the Barrier Peaks saw print. 

Third, we can see a lot more of Hargrave himself coming through. An illustration towards the back of the book is entitled “Attack of the Kill Kittens,” which gives you a sense of his humor and to the overall uncompromising nature of his games (though, considering his claim in Skull Tower of having killed over 480 player characters in four years of running his campaign, I suppose that shouldn’t be a surprise). You also get a sense of what Lawrence Schick meant when he said that Arduin is “unencumbered by good taste,” thanks to the illustration of a topless, axe-wielding woman warrior captioned “Shardra the Castrator.” As ever, your mileage will vary. 

Oh, Runes of Doom also reveals Hargrave’s preoccupation with demons, with 13 pages dedicated to new infernal entities of all stripes. I am sure he’d have been pissed had he lived long enough to see TSR remove devils and demons from D&D.