Mark of Calth – Book Review

Mark of Calth

Black Library’s Horus Heresy short story anthology Mark of Calth is themed around the aftermath of the Word Bearers’ treacherous attack on the Ultramarine planet of Calth, as described (among other books) in Know No Fear.

This is a dark book. Warhammer 40K (or 30K) at its most bleak and grim, full of atrocities, 9/11 analogies and evil chaos magics played to a gory slasher/horror-movie vibe.

However, if that is your thing, Mark of Calth is, for the most part, a surprisingly good read!

This first half of my Mark of Calth review covers the first 4 stories.Mark of Calth by various: 4 / 5 stars      

The Heresy came to Calth without warning. In just a few hours of betrayal and bloodshed, the proud warriors of the XIIIth Legion – Guilliman’s own Ultramarines – were laid low by the treachery of their erstwhile brothers of the XVIIth. Now, as the planet is scoured by solar flares from the wounded Veridian star, the survivors must take the fight to the remaining Word Bearers and their foul allies, or face damnation in the gloomy arcology shelters beneath the planet’s surface. A collection of stories by authors including Dan Abnett, Aaron Demsbki-Bowden and Rob Sanders. The battle for Calth is far from over…

The following review will inevitably contain spoilers. You’ve been warned.

Mark of Calth includes a total of 8 short stories.

  • The Shards of Erebus by Guy Haley
  • Calth That Was by Graham McNeill (at 120 pages, a novella even)
  • Dark Heart by Anthony Reynolds
  • The Traveller by David Annandale
  • A Deeper Darkness by Rob Sanders
  • The Underworld War by Aaron Dembski-Bowden
  • Athame by John French
  • Unmarked by Dan Abnett

Mark of Calth Stories 1 – 4

#1 – The Shards of Erebus by Guy Haley

Guy Haley starts the anthology with a story set before the Battle for Calth. We see Horus-Heresy-super-villain Erebus sanctify evil ritual daggers – Athame – in preparation of the betrayal at Calth. And we see him learning to “cut” himself across the Galaxy. No more tedious warp-travel (of the space ship kind) for Erebus.

Thematically, this is a solid start to the anthology, though the story is ultimately one of the less interesting ones. The Word Bearers here feel too much like mustache-twirling cartoon-villains, and Guy Haley’s attempts to show their Chaos-devotion with an obsession of the number 8 quickly gets repetitive.

Word Bearers can be cool villains, but a story solely about villains being evil, and no heroes around, feels a bit dull.

#2 – Calth That Was by Graham McNeill

McNeill’s Calth That Was is less a short story and more a 120 page novella hidden in this anthology. Here, Ultramarines and Word Bearers go toe-to-toe in the blasted, poisonous wasteland that was Calth. It’s grim, bleak and epic in scale, and Graham McNeill pulls it off really well, even throwing in a few 9/11 references.

Ultramarines and Word Bearers are two very different Legions, and this story, more than most, really manages to show the differences in how these two Legions approach the war on Calth. The second half in particular is pretty gruesome, but it also conveys the depravity of the Word Bearers better than the previous story. Overall, a good read!

#3 – Dark Heart by Anthony Reynolds

Like The Shards of Erebus, Anthony Reynolds’ Dark Heart is – for the most part – a story providing an inside-look at the Word Bearers Legion. However, where Guy Haley portrayed them as a sort of Illuminati-style secret cult steeped in archaic ritual, Anthony Reynolds’ Word Bearers are all about cutthroat competition of mostly insane and power-hungry warriors, who will stop at nothing to get ahead.

Furthermore, the story ends with a short glimpse of the Guilliman vs. Kor Phaeron duel. Dark Heart may not be the most memorable story ever, but it is a solid entry nonetheless.

#4 – The Traveller by David Annandale

The Traveller was a welcome change of pace as far as the story puts the focus squarely on the human survivors of Calth, and on their struggle with the supernatural madness engulfing their home planet.

Specifically, The Traveller deals with a human (increasingly) possessed by an evil entity (Daemon?), which tricks him and cajoles him into committing a slowly unfolding witch-hunt and blood bath among a group of caved-in survivors.

A good story with a very different point-of-view. Moreover, reading The Traveller, I almost felt like a recurring theme of “faith”, “belief” and “false belief” is running through Mark of Calth, including McNeill’s Calth That Was and Abnett’s Unmarked. If that was intentional, The Traveller was certainly the darkest take on that theme.

#5 – A Deeper Darkness by Rob Sanders

Rob Sanders adds one of his best stories yet to this anthology. Admittedly, A Deeper Darkness starts off a bit slow. The reader is introduced to a surprisingly rebellious Ultramarine (telling the story from a first-person perspective), who goes against his superiours’ wishes to explore an uncharted cave of Calth’s underworld, after the Ultramarines found a destitute Word Bearer, who had gauged out his own eyes.

In the depths of the caves, he comes across a particularly vile Daemon. The battle between the Daemon and the Ultramarine (after the Daemon killed of pretty much everyone else) feels a lot like it was inspired by Greek mythology, in a good way.

It’s rare to see interesting new takes on Chaos Daemons in Warhammer 40K. I enjoyed this one, because the story was well told and because it brought out a truly alien Daemon.

#6 – The Underworld War by Aaron Dembski-Bowden

The Underworld War is easily the most misleading title in this anthology. Especially right after A Deeper Darkness, which is all about a fight in the dark caves, The Underworld War follows a possessed Word Bearer across the blasted surface of Calth (at least initially).

I am always awed by ADB’s ability to conjur interesting characters, and Kaurtal, the Word Bearers of this story (along with his personal Daemon), is no different. Easily one of the most memorable characters in Mark of Calth.

The story’s final twist, on the other hand, left me rather cold (nor, do I think, ist he premise very plausible).

#7 – Athame by John French

Rob Sanders’ A Deeper Darkness was told from a first-person perspective. John French’s Athame is actually told from a second-person perspective. Mark of Calth is full of surprises.

The premise of Athame is to tell the tale of a weapon, one of the Word Bearers ritual Athame, as it travels from owner to owner through the ages, leaving bloodshed and betrayal in its wake. It’s a fun idea, and well done. Not  to mention that Athame includes a highly unusual cameo.

Athame is a story that could easily have  failed, but I enjoyed it a lot. Reading it, my minds eye was following the knife’s story through the eons, like a time-lapse scene in a movie showing you the passing of time. Great stuff.

#8 – Unmarked by Dan Abnett

The final story and … as much as I enjoy Dan Abnett’s work … the most disappointing one for me. Unmarked is definitely well written, though it effectivelly suffers two problems.

First, it once again delves deeply into Perpetuals (and Perpetuals going on time-travel, no less). Second, because it is about Perpetuals travelling through time and space, it fails to build any real tension.

The entire story is a bit like constantly switching channels on TV, only to see the same group of people in different sets and settings. I am sure Dan Abnett has something big and fancy planned with his Perpetuals, and I might be glad I’ve read these „side-stories“ on the Perpetual-story-arc. As a short-story in itself however, Unmarked just wasn’t very interesting.


Overall, Mark of Calth offers a collection of stories that is clearly above average. I might be a bit over-critical of Guy Haley’s The Shards of Erebus. It is – in my opinion – the weakest out of these four, but it still is a good story by “normal” Black Library standards. The other stories in this book are simply even better.

Moreover, not only are the stories pretty good, I also enjoyed the overarching themes. Mark of Calth is all about the shock, the trauma, the desolation and – in that despair – the sparks of hope in the wake of the Word Bearers betrayal.

Mark of Calth is a dark book, very much devoid of some of the more light-hearted breaks found in many other Black Library stories. It is not the kind of book I want to read on a regular basis, when I read 40K. However, it works well in the context of the post-Calth Horus Heresy story-arc.

#5 – #8 has some real gems. Both A Deeper Darkness and Athame by John French were stories that both tried to pull off something new and different, and pulled it off well.

Likewise, both ADB’s The Underworld War and Dan Abnett’s Unmarked tried to step outside the usual ideas. In these two cases, it worked less well for me, but that is likely more down to my personal tastes (like my general confusion as to where that (now time-travelling?) Perpetual-tangent is ultimately heading!).

There is nothing as such, I could fault these stories with.

It’s a truism of sorts, that every anthology has “good stories” and “bad stories”, though even the worst story in Mark of Calth still above average.