The light of the Astronomican is gone and Terra seems lost. Cut off by the Ruinstorm and faced with an unthinkable theoretical, Roboute Guilliman is forced to consider a dangerous practical: declaring the founding of a second Imperium. As Macragge becomes a beacon of hope for scattered Imperial forces, it becomes a nexus for heroes and villains alike. Because where there is light, there are shadows, and the shadows are home to the Lords of Night...

The Unremembered Empire is really the “Avengers” of Horus Heresy novels. Dan Abnett had the herculean task of tying together the stories of the Ultramarines, Blood Angels, Dark Angels, Night Lords, the primarch of the Salamanders, the Cabal, an Imperial Fist and a rogue Iron Warrior (not to mention some characters that fit into neither of these groups) that had been spread out over 26 preceding books into one novel. Mr. Abnett, I salute you.

Like an Avengers-movie, The Unremembered Empire is an entertaining story all on its own, but its real strength lies in it being a “team-up story”. The more of the prequels one is familiar with, the better the experience with the team-up. So while one could enjoy, say, the movie Avengers all on its own and have a reasonably good time with it, it gets more satisfying with every preceding Marvel movie one has already seen. And as the first Avengers-movie concluded Phase 1 and started Phase 2 of the Marvel Cinematic Universe, The Unremembered Empire is also the start of a new phase of stories for the Horus Heresy: the story-arc of Imperium Secundus.

For the Omnibus containing Empire, the real task for me wasn’t in compiling the Omnibus itself, but in arranging its prequels. I won’t bore you with all the details and different versions I went through, but at one point I had four different versions written alongside each other written down in my notes. The results are the five “Prelude to Imperium Secundus”-omnibuses: Shadow Crusade I, II & III, Anvil of War and Angels of Darkness. Reading all of these has a reader fully prepared to dive into and fully enjoy The Unremembered Empire and the rest of Imperium Secundus I: Hope’s Kindling.

The last prequels that didn’t make it into one of the “Prelude"-omnibuses were the novella The Crimson Fist and the short-story The Iron Within. Both introduce a notable character for Imperium Secundus and are therefore included in this omnibus in front of The Unremembered Empire.

I was hesitant to include The Crimson Fist again because it's already collected in two other Omnibuses, making it the only story appearing three times across the reading order. In the end, I decided to include it anyway. In all three spots it serves an important function for the storyline of the respective Omnibus it is included in, here as an introduction for Alexis Polux. I also reasoned that a reader arriving at this point in the reading order is very likely to have already bought the anthology Shadows of Treachery, so it doesn't cost additional effort/money to obtain the novella. And if they should've already read The Crimson Fist while reading Shattersong or Scale and Stone, they can skip it here and no one's getting hurt either way.

After the extensive prelude to The Unremembered Empire things get more straightforward, as the Imperium Secundus provides a haven for all these story-lines to progress together for a while, relatively isolated from the rest of the Heresy. The whole arc is told over four novels and a lot of connecting short-stories, all of which are collected in Imperium Secundus I and II.

Pharos by Guy Haley the second major chapter on the Imperium Secundus-saga. While I really liked Pharos, some of its character-arcs felt a bit incomplete to me without some of the short-stories that lay groundwork (The Laurel of Defiance, The Heart of the Pharos, A Safe and Shadowed Place) or provide epilogues for them (The Painted Count, The Aegidian Oath). My hope for the omnibus reading order is that it'll tie together these story-knots for new readers, so the story-lines can achieve their full impact.

I made an exception to include The Aegidian Oath: It is actually not a Horus Heresy, but a Warhammer 40.000-story which is set way after the Heresy has ended; I included it here because it gives important conclusion to the arc of one character from Pharos and is also a nice epilogue to the Omnibus as a whole.

There are Primarchs novels available for all the various primarchs that appear in this omnibus, so if you want to learn more about any of them, you could check them out.

Shadow Crusade I, II & III, Anvil of War and Angels of Darkness are the three narrative threads that together form the “Preludes to Imperiumm Secundus”. All three should have been read before reading Imperium Secundus I and II. Only Shadow Crusade II: Underworld War is optional in that regard.

You can consult the Flow-Chart here. Look to the upper left for the "Preludes" and Imperium Secundus I.

As mentioned before, the Imperium Secundus-arc runs relatively isolated from the rest of the Heresy. The direct sequel to Hope's Kindling is Imperium Secundus II: Fate’s Ashes, which continues and concludes the story of Imperium Secundus itself.

The Salamanders' story, which began in Anvil of War, takes its own path and is continued in Through the Neath.

The following are recommendations from other series and the wider Black Library canon. If you are interested in the characters, factions or themes that were part this omnibus, the following books might also be to your liking.

Books from the 41st millenium:

• Scythes of the Emperor by L.J. Goulding (contains The Aegidian Oath)

  • The “Scythes of the Emperor” are a successor chapter to the Ultramarines. Their home world is Sotha, the world that housed the Pharos device during the Heresy, and are haunted by the shadows of the events from millenia past. This book is an anthology of stories about this tragic band of warriors.

• Belisarius Cawl: The Great Work by Guy Haley

  • The tech-priest Belisarius Cawl is one of most important figures of “New40k”, being responsible for spearheading the Primaris-project that revolutionised the Astartes in the wake of Guilliman’s return at the turning of the 41st millenium. In this novel, Cawl ventures to the half-forgotten world of Sotha on the hunt for the mysteries that are buried there. The novel has connections to the story of Scythes of the Emperor (s. above) and has close ties with the events of Pharos.