The fourth novel in the Johannes Cabal series, The Brothers Cabal deals with Horst and Johannes, together again. Horst has risen from the dead (again) by the efforts of an occult conspiracy that wants him to be their "Lord of The Dead" and lead an army of supernatural beasts to create a homeland for monsters. Horst, naturally, wants no part of it and soon joins another secret conspiracy to fight against them-but he realizes he needs something very dangerous on his side, more dangerous than him, a superhumanly strong vampire.
He needs his brother, Johannes Cabal, necromancer.
Much of the novel is framed as a story being told to Johannes by Horst, who had chronologically met his brother at the end of the last novel, making Horst's adventures occur at the same time as some of Johannes in the Dreamlands. Johannes mostly for his own reasons but also because his brother asked (surprising Horst) decides to help stop the Ministerium Tenebrae, and uncover there is more to the conspiracy than they first thought.
The Brothers Cabal has examples of:
- Action Girl: Alisha, the ex-Prussian spy working for the Dee Society who fights the undead and shapeshifters alongside the group's other members.
- Amazon Brigade: Miss Virginia Montgomery's Flying Circus - later renamed to Miss Virginia's Warbirds - is an all-female group of entomopter stunt pilots (a job that's already insanely dangerous) who become extremely efficient once they strap some weapons on their birds.
- Badass Boast: When asked what gives him the right to go against nature and resurrect people, Cabal replies "I'm a necromancer. I claim the right."
- Back from the Dead: Horst is resurrected at the start of the book.
- The Bus Came Back:
- Orfilia Ninuka, shows up again after being absent for book 3.
- Dennis, Denzel, Rathuh Slabuth, Rufus Maleficarus and, of course, Horst return from first book.
- Call-Back: A number; this is the point in the series where the installment began to grow more connected.
- The Ministerium Tenebrae finds the old train that pulled the Cabal Bros. Carnival from the first book.
- Horst notes that he sent his brother to his death the last he saw him, a reference to his actions near the end of The Necromancer.
- Apparently, the story of Cabal saving the world from the warlock Umtak Ktharl (described in the postscript to Detective) spread out far enough that he's actually somewhat famous rather than infamous in the supernatural community. It also helps Horst's opinion of his brother.
- The castle Ministerum Tenebrae has set up in is revealed to be Harslaus, the same one Cabal was held in at the start of The Detective.
- The sorry state Mirkavia's in is an indirect result of Cabal's actions back in book 2.
- When Cabal mentions ghouls, Horst notes that he seems oddly fond of them - which is, of course, because he spent a few months as one of them in book 3.
- Catapult Nightmare: One of Horst's daytime dreams ends with him waking up like this, screaming his brother's name.
- Deal with the Devil: Cabal mentions that pretty much all necromancers have to sell their souls to the Devil to gain the ability to raise the dead. Ninuka almost did the same, but the demon she was making the deal with turned out to be Rathuh Slabuth, and when Cabal's name came up, he agreed to give her powers for free.
- Dying Moment of Awesome: The Major is trying to help Horst escape monsters and so willingly gives him a pint of his own blood. Shortly thereafter the Major is mortally wounded and Horst is still at less than max strength. Without even hesitating, the Major tells Horst to take all of his remaining blood, since he's going to die anyway.
- Enemy Mine: A group of various societies dedicated to killing vampires and warlocks teams up with Horst and Cabal to take down the Red Queen.
- Gratuitous German: A justified example, as usual with the series. The German-born Cabal brothers sometimes slip into their native language in high-stress situations. At one point, a disoriented Horst asks a stranger Vati?, despite knowing somewhere that his dad is long-dead.
- The Reveal: Who The Red Queen really is revealed in the late-middle section of the book, she's Lady Ninuka, from Johannes Cabal the Detective, now in control of Mirkavia. There's a second reveal that she is also the Lady Misericorde, quite insane, and planned the whole thing to end more or less the way it did.
- Spanner in the Works: This is double subverted with Horst and the Ministerium-they're all quite surprised at his attitude, finding him to be rather a poor example of a vampire and a bad choice for their "Lord of The Dead". So he of course mucks up their plans. But this was planned.
- Twin Telepathy: While they're not twins, at one point Horst begins to have vivid dreams of Johanness' misadventures in the Dreamlands. It takes him a while to figure out they're real, and they seem to stop after Johannes returns to the real world.
- Visual Pun: Horst notes that his colleague, Alisha is at one point slightly on fire after a battle, trying to snuff out the flames on her jacket. He then unthinkingly says "Smoking jacket" referring to the kind of jacket. Nobody finds this funny.