An evil wizard turns Casper Namlos into the hell version of a father of bastards. In short, the ill favored runt uses his bull-sized propagator to fill prostitutes with babies that burst their way out of the mothers' bodies moments after being plowed in much the same way the movie Alien far before movies or John Hurt's encounter with a predatory alien on some far flung planet in search of the next corporate payday. Joseph Hirsch begins his tale of raising Satan and his minions with a bloody battle between pirates and the defenders of a zollschloss (Bavarian castle) full of every bit of research the author gleaned in preparing for this fantasy. Like many authors unwilling to waste hours of research about the architecture of medieval castles, Hirsch sends an avalanche of the tiniest architectural feature of the castle on top of the avalanche of the technical aspects of pirate attacks without so much as a clue about how that fits into the advertised story.
After three chapters of information overload without a nod in the direction of the story of the bastard, Casper Namlos's connection with the murderous and greedy pirates, how Namlos ended up imprisoned in a barrel lined up to have his head chopped off by a giant, dipped in Greek fire, and flung into the castle courtyard, or how a mermaid came to be part of the cargo imprisoned in barrels, Hirsch finally ends up in a house of prostitution run by the mother inferior (Mother Superior), which puts the whole "Get thee to a nunnery" line from Hamlet into perspective, where the eldest bastard lusts after one of the
Once the story finally gets moving, the bastard, who hunts moss to caulk the leaking ships in port on his off hours and dreams of the dwarf who will be his future master and take him sailing the fjords and oceans, protects the bawdy house and watches the girls, Lyudmilla the object of his lust, from between the daub and wattle walls. Casper Namlos arrives at the door and pays the Abbess in silver ingots for one of the candle girls' time as long as it is in the basement, fills the girl with his abundant seed, and slips away as a demon bursts from her body to be killed by the bastard with one of the Abbess's dead husband's magic sword, saving the bawdy house, the girls, and the other younger bastards from death or worse.
The Bastard's Grimoire is a disjointed, confusing, and sometimes interesting tale of evil and magic and eventually love, though what the reader would consider the main characters make brief surprise appearances with few connections to each other -- or to the reader. What story there is -- and that is very slow going and sparse -- is readable, but only just. Without sufficient backstory, Hirsch's novel is one step above an unconnected collection of anecdotes that are somehow connected. Being written partially in German and that German not part of the mainstream canon slows the book farther and muddies the narrative waters.
The bastard -- and there is no clear indication if that is Namlos or Martin Stolzer the virgin bastard of the bawdy house -- possesses no grimoire and, other than the prodigious propagator on Namlos and Martin's relationship with Lyudmilla and the dwarf (a rock head who got away from the endless toil of hewing and shaping rock for the town cathedral to become an illuminator of religious texts in a monastery) little more is known. There is Martin's penchant for unter dem pantoffel (under the slipper which is German for the more modern pussy whipped), his virginity, and his friendship with the dwarf that render him moderately interesting. Not much more can be said for the novel or Hirsch.
Though I give The Bastard's Grimoire 3/5 stars for the few readable parts of the fantasy, I would suggest reading the novel for yourself and judge accordingly. One reader's dissatisfaction is another reader's potential favorite -- or might be in any case. Keep a German to English (or whatever language) dictionary at hand. You'll need it to understand much of the story, which is long on mystery and information dumps on zollschloss architecture and short on everything else that makes a good story, including characters, motivations, and grimoires, though full of bastards.
That is all. Disperse.