Warhammer 40K's grimdark setting besieged by terrifying bugs

The announcement trailer for 10th edition is narrated by Roboute Guilliman, the guy in charge of running the Imperium of Man. Guilliman is a son of the Emperor of Mankind, one of the 20 Primarchs who were created in a lab over 10,000 years ago to help their father conquer the stars. Guilliman was the first loyalist Primarch to re-join the setting in 40K, and he's been depresso espresso as he's tried to haul the crumbling corpse of the Imperium, a parody of his father's vision, away from the brink of extinction. As the trailer suggests, he's not optimistic about the current state of things.

He's right to worry. In recent lore, the Imperium of Man's biggest concern has been heretical, corrupted Space Marines and the extra-dimensional forces of Chaos. But there's a new bad boy on the block: the Tyranids. The Tyranids are some of the scariest enemies in 40K because, unlike Abbadon the Despoiler or a deadly Drukhari, Tyranids have no sense of humanity, communication, or emotion. They want one thing: to eat all of your bio-mass and to use it to make more Tyranids.

Tyranids have been played up as a big threat for some time, with the lore stating that the forces that originally arrived in the Milky Way were just a vanguard of a larger fleet. That larger fleet has finally arrived, and it's hitting the western side of the galaxy. The hive fleets on the eastern side of the galaxy are still a threat — the Milky Way is effectively surrounded. The Tyranids attacc, they want bio-mass, and most importantly, they see you as a snacc.

Making matters even worse, Guilliman has dedicated most of his troops far away from the western front of the Milky Way to deal with the Great Rift torn in the galaxy that split the Imperium in two. Up until now, Imperium Sanctus has been the nicer part of the 40K setting. Now, it has a big bug infestation, and even hardy Space Marines with meltaguns and flamers are getting gobbled up like bon bons.

It seems that this conflict is going to make up a big part of the narrative for 40K's 10th edition. Not only will Tyranids likely be part of the 10th edition starter box, but Space Marine 2 pits the heroic Ultramarine Captain Titus against a swarm of Tyranids.

The faction has also evolved in recent years to contain Genestealer Cults, a sub-faction with their own tabletop armies and rules. Genestealer Cults like to sneak onto a world, find a hidey-hole, and start preaching the good word. While they often appear benevolent from the outside, and the unfortunate humans who get kidnapped are forcibly swayed toward seeing them as the good guys, the Cults are in the pocket of Big Bug. Once they've built up a hidden force over generations, the Genestealer Cults attack from the inside and then summon a hive fleet to finish the job.

We'll likely find out more about the state of the galaxy as 10th edition approaches. Factions like the Aeldari and the Necrons will definitely have their own thoughts on how to stop the Tyranid swarm. The final Arks of Omen book, detailing the return of loyalist Primarch Lion El'Jonson, will also likely contain some lore as to the current state of the Imperium and how it's handling its eternal, multi-front war.