This article, The Swordfish, was written by AtanianWinter. Please do not edit this article without their explicit permission.

The Xiphiidae – widely known by their low gothic translation, the Swordfish – are a space marine chapter of the 21st ‘cursed’ founding. They are known for their unparalleled skill in subaqueous and void warfare. Records of the discovery of their homeworld, Atanis IV, in 892.M34 are the very first openly accessible official records which refer to the Rhinos space marine chapter. Alongside the Rhinos and the Angels Mortiferous, the Swordfish are now in pursuit of the traitorous Dust Lords, moving ever deeper into the Ghoul Stars.


Atanis IV

Atanis IV is an ocean planet located in the northernmost region of the Segmentum Tempestus, near the outskirts of the Segmentum Solar between Bloodfall, home of the Red Wolves, and Raikan, home of the Red Talons. For a quarter of Atanis IV’s cycle it is an ice giant, with an inhospitable, but habitable landmass. As the long summer approaches Atanis IV melts. A vast acidic ocean home to naught but perilous storms and menacing sea serpents akin to the kraken of Fenris (some speculate that both share a common, possibly Tyranid, ancestor).

As a result of Atanis IV's lack of stable landmass the Imperium overlooked the possibility of human life for a long time. In actuality Atanis IV had a flourishing, submerged human society which had endured since the Age of Strife. The savage nature of the planet produced a hardy, technologically savvy people. However, given the inherent difficulties maintaining a society beneath the ocean's surface the Atanians had not even considered becoming a space faring society once more - continued survival was enough.

The Descent of the Rhinos

In 892.M34 the local Imperial worlds began receiving transmissions stating that a mining operation on Atanis IV had discovered vast cities beneath the ocean surface. Cities that appeared to be human. Sent to investigate, the Rhinos, clad in their trademark terminator armour, requisitioned submersible vehicles. They entered the greatest of the Atanian cities with no resistance, a city named Lyonne. Soon thereafter Atanis IV joined the Imperium of Man.


As word reached Terra of the resilience of Atanis IV’s people it was quickly decided that an Adeptus Astartes chapter should be forged and stationed on Atanis IV. Unfortunately, once the endless bureaucracy involved in this decision had cleared the next founding was the 21st ‘cursed’ founding. Thus far the Swordfish have not suffered from the same bad luck as their founding brethren. Consequently they are considered to be one of the few success stories of the 21st founding.


The primogenitor of the Swordfish is not known. The Administratum have registered them as Iron Hands successors given their innate understanding of technology and use of bionics. However, it is more likely that this is a byproduct of the adaption to their homeworld, Atanis IV, than of Ferrus Manus’ gene seed. Many Imperial citizens believe the Xiphiidae to be descended of Vulkan due to their similar complexion. But, the gene seed implanted in Swordfish space marines does not alter their skin – the population of Atanis IV, their home and sole recruitment world, is predominantly black regardless. Ultimately, none but those of the highest authority know from which of the original eighteen legions the Swordfish are descended.


Lyonne is the deep sea Fortress Monastery of the Swordfish chapter. It is located on the highest peak beneath Atanis IV's vast ocean surface. Lyonne was originlly the first city of Atanis IV, a magnificent spire-city of silver and reinforced glass built long before Atanis IV joined the Imperium. Since Lyonne's birth many smaller cities have been built nearby, connected with watertight transport pipes. Nevertheless, Lyonne remains the pinnacle of pre-Imperium Atanian achievement.


The Swordfish are fairly unique in their preferred forms of warfare. Generally, the Adeptus Astartes are skilled at void warfare and prepared for subaqueous warfare should the need arise. However, on account of Atanis IV being the sole recruitment world of the Swordfish, the chapter are particularly at home in weightless environments - thriving in both the ocean and the void.

Given that Astartes with skill at subaqueous warfare are few and far between, the Swordfish are called upon to wage subaqueous war more often than void war. This has led the Swordfish to use tactical dreadnought armour and centurion armour more often than the average Space Marine chapter - these hardened armours being necessary protection against the high pressure of the ocean deeps.

Chapter Fleet

The Swordfish maintain one of the larger fleets in the Adeptus Astartes. It is composed of one Battle Barge, nine Strike Cruisers, and twenty Rapid Strike Vessels. Notably, the Swordfish fleet is large enough and organized in such a way that each company is granted a Battle Barge/Strike Cruiser and two Rapid Strike Vessels.

Known Vessels

  • Xiphias Gladius - Battle Barge, Chapter Flagship, First Company
    • Piscis Sicarii - Rapid Strike Vessel, First Company
    • Piscis Atanis - Rapid Strike Vessel, First Company
  • Relentless Cascade - Strike Cruiser, Second Company
  • Trident of Atanis - Strike Cruiser, Third Company
  • Tsunami Redoubt - Strike Cruiser, Sixth Company


The Rhinos

The chapter who rediscovered the humans of Atanis IV, the Swordfish have a special bond with the Rhinos. The people of Atanis IV are raised hearing the tales of the gray, stoic demi-gods who brought the Emperor's light back to Atanis IV. As such, Swordfish astartes have a tendency to admire astartes of the Rhinos chapter, seeking their advice and guidance. In fact, one of the closest confidants of Einar Pisc, the current Chapter Master of the Swordfish, is Akachi Masego, the current Chapter Master of the Rhinos.

Angels Mortiferous

Following the biased advice of the Rhinos, the Swordfish tend to avoid the Angels Mortiferous where possible. That being said, this is mainly a diplomatic move to ensure the strong ties between the Rhinos and the Swordfish remain as such. After all, the bad blood between the Rhinos and the Angels Mortiferous is well known.


Dust Lords

As of 999.M41, the Swordfish, the Rhinos and the Angels Mortiferous have been requisitioned by Inquisitor Lucretia Winters to hunt down the Dust Lords, who went rogue at the edge of the ghoul stars, murdering hundreds of civilians at an outpost to satisfy their new chaotic patron. The Swordfish also participated in the destruction of ++deleted from imperial records++, the Dust Lords homeworld, alongside the Rhinos. The Angels Mortiferous had not been requisitioned at this point.




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