Editing Parthorum Xenocide

{{/tg/-Heresy-Battle}}

{{Infobox 40k Campaign
|title=Parthorum Xenocide
|image=[[File:1450676988105.png|300px]]
|attacker=Imperium of Mankind
|defender=Osroene Empire
|commander1=[[Hektor Cincinnatus]]<br>[[Zorr Yenser]]
|commander2=Empress Etuili Sevoold
|date=811
|scale=sector-wide
|theatre=Parthorum Sector
|strength1=3rd [[Expedition Fleets (Hektor Heresy)|Expedition Fleet]]
|strength2=armed forces of the Osroene Empire
|casualties1=
|casualties2=
|status=Decisive Imperial Victory
|outcome= Parthorum Stream secured for Imperial shipping
}}

The '''Parthorum Xenocide''' was the Imperium's name for the first of its [[Parthorum Wars|three wars]] for the worlds of the Parthorum Sector.  Only one Osroene-authored history of the conflict exists, in the little-read annals of the Pretender Sevtal Sevoold.  Sevoold refers to this conflict as the Cataclysm, for the coming of the Imperium heralded the destruction of his people.

==Background==

The Parthorum Sector is defined by a long, stable current in the Warp beginning about 30 light years north of Terra and tracing a path north-west.  This phenomenon, known as the '''Parthorum Stream''' covers a region roughly 250 light years long and 50 light years wide at its median point.  Warp travel within the Parthorum Stream is relatively predictable and safe, and in the hundred centuries since its reconquest in the Great Scouring, only a handful of ships have been lost while in transit.

===Osroene Empire===

The Parthorum Xenocide destroyed Osroene centers of learning and killed the great majority of that race's scholars.  Human savants only became interested in the history of the lost Empire long after its annihilation and have struggled to piece together its chronology.  It is clear, however, that the realm was long-lived and stable, and judging by the anti-Imperial revolts after the war the Osroene must have been accomplished in the art of ruling over a multi-species Empire.  Although the Xenos were not as advanced as the young Imperium, they possessed the Warp Drive and had used it successfully in the tranquil conditions of the Parthorum Stream.

Osroene physiology received more attention.  Space Marine Apothecaries carried out autopsies on battle casualties and studied prisoners of war before their termination.  [[Wilmut Sachs]], on secondment from the Brothers of Death, began a substantial work on the Xenos species before the completion of [[Heralds of Hektor|First Legion]]'s operations rendered the point somewhat moot.  His notes, while somewhat redacted by Imperial censors, remain available to high-ranking Imperial citizens due to the similarities and parallels between Osroene and human physiology.  Although a definitive link was not established, there is some evidence suggesting that the species resulted from deliberate and extensive tampering with human genetics late in the Dark Age of Technology, with the weak warp presence of the Osroene held up as a telling marker.  It is one of history's ironies that these Xenos were to benefit from a lack of psykers during the warp storms of the Age of Strife only to be undone, in part, by Astrotelepathy.

===The Imperium===

Due to the limitations of calculated jumps through the Warp, the first decade of Imperial campaigns following the [[Unification Wars (Hektor Heresy)|Unification Wars]] created a fairly small interstellar state centered on Sol.  The Emperor's construction of the ''Astronomican'' on Terra increased the practical Warp jump distance one hundred fold and allowed the Imperium's [[Great Crusade (Hektor Heresy)|Great Crusade]] to reach vast territories, among them the Parthorum Stream.  [[Rogue Traders (Hektor Heresy)|Rogue Traders Militant]] were quick to move into the area and investigate.  Their reports on a stable Xenos-ruled empire in the sector caused considerable disagreement in the War Council, with [[Hektor Cincinnatus]] constantly lobbying for the permission, men, and ships to attack as soon as possible.  After months of acrimony, the Emperor issued a decree permitting the heads of individual Expedition Fleets the right to select and pursue their own objectives.

Ever confident, Hektor had begun preparing for the conquest of the Parthorum Stream while the matter was still in dispute.  His planning drew on the reports of Rogue Traders, especially Adela Exard's navigational and cultural records.  Hektor was so impressed by these records that Exard and her Cruiser ''Black Joke'' were among the Rogue Trader forces hired on to augment [[Heralds of Hektor|First Legion]] during the campaign. The Primarch also began requisitioning [[Imperial Army (Hektor Heresy)|Imperial Army]] forces to garrison his future conquests, and pressed the tech priests of [[Mars (Hektor Heresy)|Mars]] to deliver new warships.  When the Mechanicum reached the limit of their patience (or capabilities), Hektor went to Fabricator General [[Kalkas Tygian]] himself for assistance.  Tygian responded that his forges had already assigned their production, but that if the First Legion required additional warships during their forthcoming campaign that Mars would be happy to loan out their own vessels and crews.  The fulfillment of this pledge would play an important role in the Imperial victory.

==Southern Theater Battles ==
[[File:Parthorumstream+south.jpg|thumb|left|250px|Diagram of the Parthorum Stream relative to Terra.  The limit of the Southern Theater is shown by the dotted blue line.]]

First Legion's initial objectives fell in the southern reaches of the Parthorum Stream, a region roughly 50 light years in each dimension.  Rogue Traders had already roughed out the shape of subsectors based on Asturus, Hucrov, Iuybos, Scomia, and Ublade, but during the Parthorum Xenocide First Legion's commanders referred to this vast area of space as the Southern Theater.  The Osroene were aware of the limitations of their technology and relied on strong planetary defences to hold up invaders until one of their great fleets could arrive and decide the action.  Adela Exard had obtained records of such relief actions against Gallvi raiders in popular histories and Hektor Cincinnatus drew up his plans accordingly.  Rather than disperse his forces to planetary assaults and risk being defeated in detail, the Primarch's first target was the "Southern Fleet" that patrolled the region.

Hektor used Rogue Trader vessels under First Legion officers to surreptitiously hunt for the Southern Fleet.  Astropathy allowed a report from the Destoona system to be follow up on sharply and the Xenos were soundly defeated in the [[First Battle of Kopt Dara]].  However, Imperial losses compelled Hektor to return his fleet to Mars.  In order to expedite the process, Fabricator-General [[Kalkas Tygian]] personally commanded two Mechanicum warships, the ''Revelation of Victory'' and the ''Rites of War'' to take the place of the crippled First Legion cruisers ''Mount Ararat'' and ''Blessing of Thunder'' for the remainder of the campaign.  This generosity and the sterling efforts of the Mechanicum had the 3rd Expeditionary Fleet ready to resume its offensive at 201/811.M30.  Hektor split his command into three.   His own ''Chrysaspides'' formed the reserve, while the First and Second Phalanxes, reinforced with substantial fleet assets, were detached to independent compliance operations.

Erasmus Sergius's First Phalanx launched a three-pronged campaign into the Hucrov subsector.  By 293/811.M30 the lone planetary fortress at Hucrov-6 had fallen to Space Marines deployed by Thunderhawk and the planetary government capitulated rather than face annihilation at the guns of the Imperial fleet.  Nearby Thucerus was better-defended and its orbital installations had to be reduced by First Legion's warships before occupation began, but again the defenders swiftly surrendered once their space defences were neutralised at 295/811.M30.  Only at Xabradus did Sergius's men face sustained resistance.  Here small teams of Space Marines were once again successful in disabling the planetary fortresses, but the ground defenders remained resolute.  With reports of a substantial human population on-world, Strategos Bacchides Floridius felt unable to conduct a strategic bombardment and instead committed further ground forces to the surface.  Floridius's naval support, in particular the sophisticated ''Rites of War'' did carry out tactical and operational bombardments, acting as orbital artillery for the Space Marines below.  Xabradus was declared pacified at 303/811.M30 and handed over to a powerful garrison based around regiments of [[the Carlisian Shock Troops]].  Supply records indicate that the auxilia were still mopping up resistance for months to come, but the Adeptus Astartes were free to continue their conquests.

Second Phalanx, commanded by Lysimachos Fabius, were free to concentrate their efforts on the well-defended Scomia system.  Like their battle brothers at Xabradus, the warriors of the Second were glad to have a Mechanicum warship with them.  The advanced armament on the ''Revelation of Victory'' out-ranged the defenders' void weapons.  Although Fabius was not prepared to engage in a lengthy stand-off engagement, ''Revelation of Victory'' badly damaged one of Scomia-2's orbital fortresses shortly after the void battle began at 292/811.M30.  This good fortune allowed Space Marines to make surface and take out the planetary guns before the void battle drew to a close.  The Imperial fleet finally disabled all three orbital installations and commenced landings in force at 294/811.M30.  Osroene troops put up a spirited resistance but the thousands of Space Marines under Fabius's command harried them relentlessly, waging around-the-clock warfare that the Xenos were physically incapable of withstanding.  Second Phalanx signaled at 317/811.M30 that organised resistance on Scomia-2 had ceased.

Although Hektor was pleased by the progress of his gene-sons, he was anxious to capitalise on what time remained before the Osroene could respond in force.  Determining on a bold course, he signaled Mars to request additional voidships and took his own ''Chrysaspides'' back to Destoona.  The system's main inhabited world, Jeglora, was secured at 370/811.M30.  This attack briefly seemed like recklessness when a large Osroene fleet arrived in system at 418/811.M30, but Hektor's void tactics allowed his command squadron to stay clear of the aliens until Mechanicum reinforcements led by [[Zorr Yenser]] arrived at 445/811.M30 and forced the decisive [[Second Battle of Kopt Dara]].

==Sevoolda System Battles==
[[File:1449471737962.jpg|200px|thumb|right|Empress Etuili Sevoold]]
Following the destruction of the Osroene void power at the Second Kopt Dara, Hektor launched an audacious strike at the Xenos throneworld with a combined force of Space Marines, Mechanicum warships, and [[Rogue Traders (Hektor Heresy)|Rogue Trader]] forces.  Although the speed of Imperial warp travel caught the Osroene off-guard, the defenders quickly concluded that they had suffered another reversal in the Destoona system and concentrated their forces under the guns of War Fortress Tzor.  Hektor led a boarding torpedo assault and his personal prowess not only averted disaster but led to the capture of the great station.  With the Osroene defences unlocked, the Imperial fleet won its final, costly void victory in the Parthorum Xenocide.

Empress Etuili Sevoold responded to defeat in the void by offering surrender.  She first offered to split her domain with Hektor, granting the Primarch all of the stars between Sevoolda and Terra.  When that was rejected, the Empress then pleaded to reign only over her people's homeworld, and finally offered herself as consort to the conqueror if only the Osroene would be permitted to live on as thralls to Terra.  Such pleas were in vain.  Hektor Cincinnatus had not come to the Parthorum Sector to parley with the Xenos, but to destroy them.  Even as Etuili Sevoold begged for peace, the Imperial cohorts were preparing to land on Sevoolda.

It must be said that the Osroene fought heroically in defence of homeworld and legacy, but they had no real answer to the ferocious Space Marines, let alone the god-machines of Legio Tempestus.  The Xenos legions collapsed under the pressure of the Imperial attack.  Erasmos Sergius's warriors dragged Etuili Sevoold from her palace and executed her without trial.  The Imperial commanders were less concerned with the strength of resistance than with the presence of human soldiers among the defenders.  The Great Crusade was a mighty struggle to destroy the dominion of Xenos over the Galaxy and establish man as master - what cause had humans in resisting such a mission?  Hektor's officers did not stay their hands, but many remembered their concerns when the news broke of rebellions in the Parthorum Sector.

==Aftermath==

After destroying the centres of Osroene rule, the Space Marines of First Legion moved on to new conquests.  Behind him, Hektor left behind a region of space nominally under the rule of the Imperium, but actually in anarchy.  Bringing the worlds of the Parthorum Sector into order was left to the Imperial Army.  Records of these compliance actions are fragmentary at best, especially after the destruction of the [[Hektor Heresy]].  The evidence points to a vast transfer of militia forces, plus at least seven independent Compliance Groups of uncertain size.  Gufarnus Altmakar's memoirs describe "millions" of fighting men in sector even before rebellion broke out on Sulas-7.

==Imperial Order of Battle==

For the outset of the campaign, Hektor had expanded his 3rd Expedition Fleet with the vessels and flotillas of several Rogue Traders Militant.  The precise make-up of the forces under command of these idiosyncratic leaders is in doubt and the limited records available often contradict one another.  The order of battle described below is therefore somewhat speculative.

* 3rd Expedition Fleet - Primarch Hektor Cincinnatus
** Naval Task Force - Navarch Basileus Orion Mucius
*** Rogue Trader Flotilla (Lord Captain Megasu Athon) - Syntagma Euthymios Varius
*** Rogue Trader Cruiser ''Black Joke'' (Captain Adela Exard) - Ouragos Markos Priscus
*** Rogue Trader Cruiser ''Hawk'' (Captain Hubert Fulton) - Ouragos Tecton Egnatius
*** Cruiser ''Rites of War'' - Magos Prime Arnav Davix
*** Cruiser ''Revelation of Victory'' - Magos Prime Aisaak Kamern
** ''Chrysaspides'' - Strategos Hephaestion Horatius
** 1st Phalanx - Phalangiarch Erasmos Sergius
** 2nd Phalanx - Phalangiarch Lysimachos Fabius
** Various Auxilia formations drawn from the Solar Auxilia and [[the Carlisian Shock Troops]].
* Void Congregation Yenser - Archmagos Prime Zorr Yenser