The Fourth Tyrannic War is the latest and biggest Tyranid offensive yet, launched by Hive Fleet Leviathan into the Western Reaches during the Era Indomitus. It’s the conflict that turned a distant xenos threat into a full-blown crisis for the Imperium.
What started it
After the Imperium had barely contained Leviathan’s earlier pushes, a fresh assault erupted in the Western Reaches of Segmentum Pacificus. This wasn’t a single fleet but three massive tendrils, which the Imperium named Nautilon, Promethor, and Grendyllus.
The first two were met with the Imperium’s Solblades and Anchor Worlds strategies, which seemed to be holding. Then Grendyllus appeared from below the galactic plane, undetected, and started swallowing territory before anyone on Terra realized what was happening.
The Battle of Bastior
Grendyllus drove straight for the Bastior Sub-sector, a key region that included the Formidyre System and the world of Sanctum. Lord Commander Solar Arcadian Leontus was coordinating the war effort from the Phalanx, which was anchored at Sanctum.
When Groupmaster Tysen Yacobe’s task forces went missing, he took his remaining ships deep into the sub-sector to buy time. But the Shadow in the Warp descended, driving astropaths insane and spreading panic. Grendyllus bypassed many of the Imperium’s defensive lines, forcing a desperate counterattack.
- Location: Bastior Sub-sector, M42
- Outcome: Imperial tactical victory, but many worlds lost and Tyranids remain
- Key Imperial commanders: Lord Commander Solar Arcadian Leontus, Captain-General Trajann Valoris, Captain Tor Garadon
- Tyranid leader: The Swarmlord (missing in action)
Why it matters
This war shows the Tyranids aren’t just a fringe problem anymore. They’re hitting the Imperium’s heartlands, and even with heroes like Leontus and the Phalanx, the best the Imperium can manage is a costly holding action.
It also ties into the Era Indomitus, the current setting where the Imperium is stretched thin on all sides. The Fourth Tyrannic War is one of the biggest reasons why.
How it connects to the other Tyrannic Wars
The Tyrannic Wars are a series of conflicts against different Hive Fleets. The first was Behemoth, stopped at Macragge. The second was Kraken, barely defeated. The third was Leviathan, which is still ongoing.
The Fourth Tyrannic War is essentially a new phase of the third, with Leviathan returning in even greater force. It’s not a separate war but a continuation, and it’s the largest Tyranid invasion yet.
Key facts
- The Fourth Tyrannic War is Hive Fleet Leviathan’s largest invasion yet, hitting the Western Reaches in the Era Indomitus.
- It involves three tendrils: Nautilon, Promethor, and Grendyllus.
- The Battle of Bastior was a major campaign, ending in an Imperial tactical victory but with heavy losses.
- Lord Commander Solar Arcadian Leontus and the Phalanx were key Imperial assets in the war.
- The war is a continuation of the Third Tyrannic War, not a separate conflict.
FAQ
When did the Fourth Tyrannic War start?
It began during the Era Indomitus, after the Great Rift opened. The exact date isn’t clear, but it’s the most recent major Tyranid offensive.
Who won the Battle of Bastior?
The Imperium won a tactical victory, holding Bastior, but many worlds were lost and the Tyranids are still active in the region.
What are the three tendrils of the Fourth Tyrannic War?
They’re named Nautilon, Promethor, and Grendyllus. Grendyllus was the most dangerous, appearing unexpectedly from below the galactic plane.