- "We are the slayers of kings, the destroyers of worlds, bringers of ruination and death in all its forms. These things we do in the name of the Emperor and in the defence of Mankind. Let none stay our wrath."
Cato Sicarius is the current Captain of the Ultramarines 2nd Company. His titles include Master of the Watch, Knight Champion of Macragge, Grand Duke of Talassar and High Suzerain of Ultramar. He is known as one of the greatest of the Ultramarines' heroes, and is also said to be the heir apparent to Marneus Calgar, the current Chapter Master of the Ultramarines and the Lord of Macragge. Each of these honours reflects only a fragment of an entire lifetime of diligent and extraordinary service to the Realm of Ultramar and the Emperor of Mankind.
Master of the Watch
Sicarius was born and raised in the ducal household of Talassar, one of the most prominent of Ultramar's noble dynasties. Even before he could walk and talk, Sicarius was being guided towards the martial arts. By the time of his fourth birthday he could wrestle, sword fight and shoot to the satisfaction of his masters, and as he grew, his schooling in matters of warfare intensified. The training masters in the Talassari agoge pressed the young noble hard, sensing his gift and the glorious future that it offered for their household were it honed sufficiently. At ten years old, he could outfight youths twice his age with consummate ease, and he was developing strength and stamina to match his skill. The house savants sought to marshal his intellect equally to his physique, teaching him history, poetry and the laws of the Imperium. For all the academia that was poured into his young mind, however, it was always the thought of battle, the thrill of competition and a yearning for victory that drove him onwards. His tutelage in the ways of war was only reinforced by his later induction and training amongst the Ultramarines Chapter. When he was recruited into the Ultramarines, Sicarius earned commendation after commendation and rose swiftly through the Chapter's ranks. In the decades that followed, he served as Sergeant and then 2nd Company Champion before ultimately assuming the command of the 2nd Company himself.
Several centuries later, Sicarius is the Master of the Watch, Captain of the Ultramarines 2nd Company and, by rank, the third most influential man within the Chapter. The authority of the 2nd Captain is eclipsed only by Captain Agemman of the 1st and their liege, Chapter Master Marneus Calgar. As Master of the Watch, Sicarius is tasked with the defence of Ultramar, overseeing a staff of thousands of planetary defence force commanders and generals on both his home world and the surrounding systems in the Ultima Segmentum. Without doubt, Sicarius has found the responsibility of ensuring Ultramar's safety especially difficult in the wake of the Behemoth invasion, for the Tyrannic threat continues to increase, as do the predations of the Tau on the Eastern fringe, the Orks in what remains of the Arch-Arsonist's empire and the recent and recurring engagements with the Necrons. Were matters martial not a grave enough concern, Sicarius is also responsible for the prosecution of those within the Chapter whose infractions breach the sacred laws as laid out by the Codex Astartes. This is a solemn task, and many would think ill-suited to the relatively loud, brash Sicarius, but as with everything he attempts, Captain Sicarius has taken to it with a vigour bordering on zeal. Those who have emerged from a tribunal with Sicarius are often shaken, and usually humbled. It is perhaps telling that fewer defendants have chosen trial by combat against the Second Captain than any other Master of the Watch in the past three thousand years.
Knight Champion of Macragge
While many of the duties that fall to Sicarius, by dint of his office as Captain of the Second, involve officiating, planning and a large degree of bureaucracy, there is no doubt that the role to which he is best suited is that of Knight Champion of Macragge. Twice in his career Sicarius has served as a Company Champion, first to Captain Idaeus of the 4th and later to Captain Invictus of the 1st Company. It is a mark of how great a warrior and protector Sicarius is that in both those tenures, neither Captain came to any serious injury. Some within the Chapter whisper that Sicarius' apparent venom towards Captain Ventris of the 4th, during his trial following the Tarsis Ultra debacle, was due to the Suzerain's fondness for the late Captain Idaeus, beside whom he had fought during his own time in the 4th Company.
As Knight Champion, Sicarius must answer challenges addressed to the Chapter as a whole and he has done so with startling and bloody results on many occasions. When Inquisitor Orchaedes denounced the precognitive abilities of Chief Librarian Varro Tigurius as evidence of forbidden pacts with the dark powers of the Warp, the accusation was met by the Chapter with the derision it deserved. However, Orchaedes pressed the issue, demanding an audience with Chapter Master Calgar. The trial took place in the Temple of Corrections, with more than a hundred Space Marines standing watch. As Orchaedes spat forth his anti-psyker rhetoric, scorning the good name of Tigurius and the honour of the Chapter that shielded him, the Ultramarines listened. To his credit, the Inquisitor was undaunted when Calgar's voice cut through his tirade like a peal of thunder, and only blanched slightly when Captain Sicarius, clad fully for war, descended from the left hand of his master to issue a challenge under the laws of trial by combat.
For his part, Orchaedes had a champion of his own, and from within his personal army of acolytes, confessors, sycophants and soldiers emerged a hunched and hooded figure. Sicarius pointed with his sword, the legendary Talassarian Tempest blade, and ordered his opponent to show himself. Slowly the robes dropped to the ground to reveal a battle-class chrono-gladiator, which raised itself to full height on Skitarii-grade servo limbs. Roughly simian in shape, the chrono-gladiator was the height of a Space Marine in Terminator Armour and covered in strength-enhancing servo bundles and interlocking plates of armoured carapace. Designed for one-on-one combat, it combined Adeptus Mechanicus gene-science, hundreds of hours of augmetic surgery and the mind of a psychopathic killer. "Naogotha," the Inquisitor hissed, slowly pointing his finger at Captain Sicarius, "Kill him."
Although Sicarius could never have seen it with his eyes locked on his newly unveiled foe, his liege, Marneus Calgar nodded once at Orchaedes as the battle began. Stim-activators surged into life, pumping frenzon, 'slaught and a dozen other war chemicals into the chrono-gladiator's frame, and it raised up a power flail and stun maul in its over-muscled hands. Sicarius did not pause for a moment, but advanced the twenty or so paces to the slathering techno-brute before him. The chrono-gladiator rushed forwards, thrashing at the Space Marine with every step. Sicarius dodged a crushing downward blow from the shock maul that fractured a flagstone in an explosion of marble, stepped back from a sweeping attack from the power flail that could have beheaded a Terminator, and parried its backswing in a shower of sparks. His lip curled in snarling anger, Sicarius drove his knee into the construct's stomach, forcing it back, and smashed his off-hand into the stim-injectors around its face. Before the chrono-gladiator could retaliate, he danced back, using the length of his Tempest Blade to hold it bay. Again and again, the Captain used his blade only to block and parry, instead crushing armour plates with his bludgeoning fists. Twice he tripped his foe to the ground, before stepping back to allow it to rise. Minutes turned to hours, and the chrono-gladiator's movements became laboured, the swings of its weapons clumsier and slower. The stimm-injectors feeding its frenzied movements ran dry, and it stumbled and fell, limbs thrashing and twitching until it was still. Sicarius' sword was unbloodied, and slowly he looked from his prone foe to the Inquisitor, whose mouth was silently working, as if to utter some dire proclamation.
"It is time you took your men and left Ultramar," Sicarius spoke, his tone low with menace. The Inquisitor's voice broke into a shrill cry as he strode towards the Space Marine -- all eyes in the hall, Adeptus Astartes and Inquisitorial retinue alike, looked on in horror. The Inquisitor stopped five paces from Captain Sicarius, a tirade of vitriol spewing from his lips as he denounced Tigurius as Warp-tainted and corrupt, and Sicarius as a whoreson and a lackey. As his rant rose in volume and invective, Orchaedes reached to his belt, perhaps for his rosette of office, or perhaps for his archeotech pistol... In a blur, Sicarius lunged forwards, swinging the Talassarian Tempest blade up in a savage arc that struck Orchaedes just as his hand emerged from the robes, slicing through the flesh and bone of his wrist. As Orchaedes' hand flopped to the ground, nerveless fingers clenched around the grip of his pistol, the Captain turned to face the Inquisitorial retinue, some of whom scurried forward to bear up their master, while others looked panicked enough to reach for weapons.
With a snarl, Sicarius stamped forwards with a power armoured boot, crushing the severed hand and the precious pistol it still clutched into a meaty paste. He paused a moment longer, to drive his blade into the skull of the prone chrono-gladiator, before ordering the Inquisitor's followers to take their master and depart, never to return. As his words died down, one hundred Space Marines raised their bolters and racked the slides. Lord Calgar stood from his throne and, quaking with fear, Orchaedes' retinue filed out, their master's querulous cries for justice and vengeance going unanswered...
Assault on Black Reach
While his service as Knight Champion has been exemplary, there are those who would argue that Cato Sicarius is ill-suited to the practical duties of commanding a Battle Company, and they hold as examples battles that have seen the 2nd Company tested to the very limits of its endurance -- battles such as the Assault on Black Reach, where Sicarius' highly aggressive tactics thwarted a major offensive spearheaded by the unusually cunning Ork Warboss Zanzag. The culmination of that campaign took place within the Ork Warboss's underground lair, where the heart of Zanzag's WAAAGH! was ended in a spectacularly violent fashion after terrible losses to the Ultramarines 2nd Company. During this campaign, the entire 2nd Company was deployed against a force numbering some 10,000 Greenskins. When the Astartes ultimately ran out of ammunition against the savage xenos, Sicarius ordered them to use Combat Knives and Chainswords until every last Greenskin had met its end. The Warboss was eventually slain, his head taken by Sicarius in personal combat. At the battle's conclusion, only a single Terminator and 12 Battle-Brothers from the 2nd Company had been slain during the Ultramarines' operations on Black Reach. It is certain that Sicarius and his warriors saved the world of Black Reach from the clutches of the Orks, but voices within the Chapter council whispered that the cost was too great.
In 878.M41, roughly twenty years after the prosecution of the Black Reach campaign, Sicarius crossed swords with a foe that would come to haunt him repeatedly for more than a century. An attack by Chaos raiders revealed itself to be masterminded by the Daemon Prince M'kar known as the Reborn or the Thrice-born in various records. Sicarius commanded the Ultramarines strike force that faced the Forces of Chaos during the Battle of the Halamar Rift and his Strike Cruiser Valin's Revenge and its Escorts managed to defeat most of the Chaotic warfleet. However, after the Ultramarines boarded the main Chaos warship, Sicarius failed to kill the Daemon Prince. Sicarius triumphed in a space battle that broke the back of the Chaos forces, and forced his daemonic foe to retreat into the Warp. M'kar would return twice more to the Ultramar System, finally returning for vengeance with a force of Iron Warriors that required the combined strength of the entire Ultramarines Chapter to vanquish. In these times, Sicarius led his warriors with an iron will -- unflinching in the face of the daemonic and unnatural.
In 974.M41, Sicarius led an assault against the recently awakened Necrons that had overrun the resource-rich Mining World of Damnos, which was also a Necron Tomb World. Unable to land heavy weaponry and ground vehicles due to skyfiring Gauss Pylons, the Captain relied on the use of his infantry in a two-pronged Drop Pod insertion. The first group, led by Chief Librarian Tigurius, was tasked with the destruction of the Necron artillery situated on the hills of Thanatos. Once this objective was met, the Ultramarines could field tanks and Thunderhawk gunships to better counter the xenos with their heavy guns. The second group, led by Captain Sicarius, was to relieve and liberate the only surviving human city on Damnos, Kellenport, the planetary capital.
Chainsword and Bolter brought the fury of the Adeptus Astartes to the Necron phalanxes, but even when the Space Marines had joined forces with the surviving Imperial Guard troops present on the world, the xenos did not bow and were ever ruthless and indomitable. Sicarius himself cut down dozens of Necron raiders and single-handedly crippled a looming Necron Monolith with a well-placed Melta-Bomb, but these heroics barely slowed the enemy's advance. In frustration, Sicarius sought to buy more time for Tigurius's strike team by assaulting the supreme Necron Overlord, known as "the Undying." The duel proved closely matched, but the Necron leader's raw strength served as the deciding factor when his Warscythe cut deep into Sicarius' torso and grievously wounded the Ultramarine officer. Roaring in anguish, the Venerable Dreadnought Agrippan stormed through the Necron ranks to protect the body of the fallen Captain and crushed the xenos overlord. This led the rest of the xenos army to revert to vulnerable defensive protocols that the Ultramarines briefly exploited.
Meanwhile, Tigurius' forces had managed to destroy the Gauss Pylon battery, which allowed the Ultramarines to land tanks and gunships. However, despite their best efforts, the Ultramarines were eventually forced to evacuate the surviving citizens and withdraw from Damnos. This course of events became known as the Damnos Incident, and the world was lost to the Necrons and classified as a Forbidden World by the Imperium.
It can be argued that since Sicarius and his men were able to evacuate large swathes of the world's population from certain death, the mission was not a complete failure. However, the fact remains that the Ultramarines failed in their primary objective of destroying the Necron threat that had emerged on Damnos.
Sicarius was determined to not let such a slight go unanswered for long. For the first time, he had tasted bitter defeat in battle and it was a black mark that would twist within his breast for the next twenty-five standard years. In future battles, his violent displays of courage became reckless to the point of unnecessarily endangering the lives of his men and every victory after Damnos rang hollow to him. In the aftermath of Damnos, as Sicarius recovered from the wounds he had suffered, Sergeant Chronus was by unanimous assent honoured with the title of "Spear of Macragge", a title rarely bestowed in the history of the Chapter and only given to an Astartes who was considered a great hero of the Ultramarines. Some say this was a move by Sicarius' detractors to lessen his influence.
Legacy of Victory
Sicarius commanded the Imperial operations during the Fall of Medusa V in 999.M41 and deployed his forces across the world to take up defensive positions before finally giving the order for an Exterminatus of the planet following a long and bloody campaign.
Captain Sicarius led his company and the forces of 30 other Space Marine Chapters and Imperial Guard regiments during the Zeist Campaign in 999.M41 against the forces of the Tau Empire, which were seeking to expand into Imperial space on the Eastern Fringes of the galaxy. By the time the Imperium moved to counter the Tau expansion, 26 Imperial worlds had already been claimed by the servants of the Greater Good. The forces of the Imperial Guard and contingents of Astartes from the Night Watch, Halo Dragons, Silver Skulls, Crimson Fists and other Chapters joined Sicarius and his Ultramarines on the world of Praetonis V to coordinate the Imperial defence and counteroffensive. Sicarius chose to deploy his forces using the same tactics of mobility and precisely targetted firepower that had allowed the Tau to claim so many successes. The combined Imperial strike force reclaimed all of the 26 planets that had been annexed by the Tau and badly blunted the Tau's offensive, forcing them to delay their 4th Sphere Expansion until they recovered from the heavy defeat inflicted by the Zeist Campaign. But before the Imperium could launch a full counter-invasion of Tau space, the High Lords of Terra recalled the force to deal with the onslaught of the 13th Black Crusade.
When Sicarius and the 2nd Company returned to Macragge in 854.999.M41 they discovered that the Realm of Ultramar had come under assault by the Forces of Chaos led by the Daemon Prince M'kar the Reborn. The entire Ultramarines Chapter was despatched to protect all the worlds of Ultramar that were under attack, while Marneus Calgar joined Sicarius and the 2nd Company to defend Sicarius' storm-wracked homeworld of Talassar from the Chaotic assault. After a fierce campaign, M'kar was finally slain and banished back to the Warp by Calgar, who promised that he would slay the foul Daemon Prince a hundred times more if such was required to keep Ultramar and the Imperium safe from his corruption.
Courage and Honour
Only the most accomplished of warriors could hope to command the Ultramarines 2nd Company and Sicarius rose to that challenge as he had to all the others in his life. All Astartes make use of the lightning assault as their preferred combat doctrine, but Sicarius refined this tactic to near-perfection and often committed his forces to combat with only the briefest appraisal of the tactical situation. In another man, such haste might seem reckless or unwise, but Sicarius possessed an unparalleled ability to adapt to the chaos of war and proved capable of easily marshalling his forces and seizing the advantage in almost any combat situation. Sicarius' assaults always took a fierce toll amongst the foe, in both numbers and morale. Even other Astartes were often left in awe by the sheer speed with which Captain Sicarius could analyse and then react to a rapidly-evolving tactical situation.
In the course of his service to the Chapter, Sicarius earned a wide variety of battle-honours. His artificer armour, the finest in the armouries of Macragge, bears solemn testament to his service, with the Victorex Alpha hanging from his waist, the Eternium Ultra which set him apart as the High Suzerain of Ultramar, the Imperial Laurel, earned after the Crusat Minor Planet Strike in 733.M41, the Honorifica Valorum after the Battle of Dyzanyr, and the Valour Crest following the Battle for Fort Telendrar. Amongst the political positions awarded to Sicarius as a high-ranking officer of the Ultramarines was that of Grand Duke of Talassar, his homeworld, and Suzerain of Ultramar in 849.M41. Each of these glories has been won through courage and honour, and none can say they are undeserved -- for thousands of foes lie dead at his hand in testament to Sicarius’ prowess. Whatever his detractors may say, whatever ill fate he has brought upon himself through his battles with Daemons, xenos and traitors, Sicarius remains ready to serve -– and will fight with all the might of the Chapter's greatest champion until he dies in its service.
In time, Cato Sicarius' very name became a byword for Imperial victory, a legend that came to the ears of allies and foes alike far beyond the borders of Ultramar. At the close of the 41st Millennium, the Ultramarines 2nd Company always draws the most dangerous missions assigned to that Chapter and Sicarius is believed by most Ultramarines to be a fitting heir to become the Ultramarines' Chapter Master and Lord of Macragge when Marneus Calgar finally passes to join the Emperor. This sentiment amongst his comrades probably does not sit quietly with Severus Agemman, the Captain of the Ultramarines 1st Company and the current Regent of Ultramar.
Return to Damnos
Despite the Inquisition's efforts to suppress all knowledge of the Necrons' reemergence into the galaxy, the Imperium's faith in its military supremacy was shaken by the news that spread across the galaxy after 974.M41 that these xenos had overcome both the Imperial Guard and the Ultramarines at Damnos. Eventually, reports of the loss of Damnos made their way to Terra, where both the Fabricator-General of the Adeptus Mechanicus and the High Lords of Terra decreed that the Ultramarines must return to Damnos and eradicate the Necron threat once and for all.
Twenty-five standard years after the Damnos Incident, in 999.M41, this Imperial order was brought to Macragge by the experienced Deathwatch strike team led by Squad Lazarius. Chapter Master Marneus Calgar was not pleased with the Imperium's decree, for he knew that his 2nd Company had faced only a fraction of the awakened Necrons on Damnos a quarter of a century before. Once they returned to Damnos, the Ultramarines would face the entire strength of a Necron Tomb World and risk the deaths of hundreds of the Chapter's Astartes. Yet, Calgar knew that the High Lords of Terra were right and that the Necrons on Damnos must be defeated if the Imperium was ever to know peace in the face of the growing Necron threat. With the record of the Ultramarines stained by the action on Damnos, it was their duty to banish the ghosts of the past. Upon hearing Calgar's announcement that the Ultramarines' 1st, 2nd, 3rd, 5th, and 6th Companies, accompanied by elements of the 10th, would return to reclaim Damnos for the Emperor, Cato Sicarius smiled for the first time in decades. It is said that during the preparation for the assault, Sicarius trained so hard that he fought with the fury of a man possessed and even slept in the cage-vault. Before the solar month was out, Calgar's armies and fleets had been assembled and over 500 Space Marines stood ready for war. In addition, Sicarius was granted a Vortex Grenade by the Deathwatch Sergeant Davian Imocles, who was rumoured to be an old friend and former squad mate.
The journey to Damnos was a perilous one, with Calgar relying on various ruses and distractions to get his warriors safely to the planet's surface. By the time the Necrons had spotted the true location of the Ultramarine warships, the Astartes fleet was in a position to launch their Drop Pods. The first wave consisted of unmanned variants designed to draw the fire of the Gauss Pylons. The second wave, however, represented the true assault, which brought hundreds of Space Marines as well as a number of vengeful Imperial Guard regiments to the heart of the Necrons' subterranean tomb complex.
Their objective was to destroy the pyramidal complexes that controlled the Necron power grid and to do it before the Imperial forces were overwhelmed. However, one factor that they did not account for was the physical incarnation of a C'tan held within a Tesseract Vault. It was determined that this vault was the true source of the Necrons' power and must be neutralized if the Imperial forces were to have any hope of victory. Despite the power brought to bear by the Imperial assault on Damnos, Marneus Calgar felt like a duelist being taken apart by a superior foe in the battle-cage. The xenos' battle logic proved impeccable, with its master intelligence anticipating the Ultramarines' every move and neutralizing each tactic they employed. Thanks to an energy shield emitting from the vault, every plasma volley and melta blast employed against the Necron Monoliths dissipated harmlessly or detonated prematurely before it could harm the constructs.
Since the xenos had managed to analyze the Ultramarines' battle doctrine, Calgar realized he must attempt a completely unexpected strategem. Assaulting the ranks of the Necron Immortals, the Chapter Master jumped onto the metallic base of a malfunctioning Gauss Pylon and slowly pushed the war engine's crescent back until its viridian beam hit the energy shield of the floating necropolis. With a blinding flash of light, the energy shield protecting the tomb complex collapsed and the Tesseract Vault was broken wide open to reveal the enraged demigod imprisoned within. A giant cruciform of pure light rose above the Necron army, the remnants of the C'tan's energy cage still crackling around it. Roaring in exultation at its newfound freedom, the booming sound threw Ultramarines and Necrons alike to the icy ground and cracked the planet's crust. Its first victim would be the Necron Overlord, the Undying, which the star god crushed with ease by transforming the earth around his metallic form into an oversized fist.
The Overlord phased out of reality, seeking to escape back to his subterranean lair. But deep underground, the surviving members of the Deathwatch's Squad Lazarius had reached their own objective. The Undying teleported back to his cabled sarcophagus right in front of the Deathwatch's eyes. Unfortunately for the Necron, the crack team of Astartes had replaced his revivification engines with melta charges and entropic destabilisers and proceeded to blast the Necron Overlord into atoms. Back on the surface, the xenos reeled from the loss of their leader and the artificially intelligent command programs that had governed their warriors' every action. Meanwhile, the unleashed C'tan lashed out in fury at both its Necron enslavers and the Ultramarines as Captain Sicarius duelled a Flayed Ones Lord. After ramming his Power Sword into the powerful Flayed One's torso, Sicarius summoned twenty-five years of anger and frustration into a final burst of strength. He unclipped the Vortex Grenade that had been given to him earlier and activated the weapon before throwing it at the enraged demigod hovering overhead. The grenade detonated and formed a spiralling orb of nothingness as its unstoppable force sucked the C'tan into the Warp before collapsing and winking out of existence. Sicarius felt a great weight lift in that moment, as he realised both he and the Ultramarines had been redeemed for their original failure on Damnos in the sight of the Emperor.
Over the next few solar days, the Imperials eliminated the surviving Necrons with grim efficiency. Empty tomb complexes were collapsed or detonated under the guidance of the Deathwatch and the citizens of Damnos whom Sicarius had rescued decades before were restored to the world to reclaim it for their own.
Resurrection of Guilliman and the Terran Crusade
In 999.M41 the Ultramarines Primarch Roboute Guilliman was resurrected on Macragge through the efforts of the Celestinian Crusade made up of the survivors of the fall of Cadia and their allies among the Eldar Ynnari. As Guilliman immediately moved to reclaim leadership of both the Ultramarines and his former stellar empire, Captain Sicarius played a key role in the Primarch's campaign to liberate the worlds of Ultramar from the massive assault by the Forces of Chaos that was part of the 13th Black Crusade. But the war across Ultramar was still ongoing when Duilliman realised that his true duty lay beyond the boundaries of Ultramar -- he had to defend the Emperor's faltering Imeprium. To this end, Guilliman announced that he would undertake the Terran Crusade through the growing Warp activity that was increasingly disrupting travel and communications across the galaxy to reach the Imperial Throneworld. There, he would meet with his father the Emperor of Mankind for the first time in ten standard millennia and ask for guidance.
As such, Guilliman gathered a select force of Battle-Brothers from the 1st, 2nd and 3rd Companies of the Ultramarines to accompany him to Terra, and gave the honour of their command to Cato Sicarius. He further requested that Grand Master Aldrik Voldus and the Grey Knights of the 3rd Brotherhood join their Crusade. Others pledged their aid to the Primarch's cause, including the assembled strength of the Ultramarines' Primogenitor Chapters, and the Emperor's Champion Marius Amalrich and his Black Templars brethren. Saint Celestine, the Inquisitor Katarinya Greyfax and Archmagos Dominus Belisarius Cawl also accompanied the Primarch -- whatever aid they or the military forces under their command could provide the Primarch would be gladly given. Guilliman gratefully accepted all offers of aid before commanding Marneus Calgar, Chief Librarian Varro Tigurius and Captain Severus Agemman to remain and lead the reconquest of Ultramar.
During the Terran Crusade, Sicarius was given the honour of serving as the commander of the Primarch's Victrix Guard, an elite formation of Ultramarines Astartes chosen by Guilliman after his resurrection to accompany him on the Terran Crusade. Hand-picked by the Primarch himself to act as his bodyguards and diplomatic envoys, the Victrix Guard seek to excel in every aspect of battle and statecraft alike. Veteran Marines with countless standard centuries of combat experience between them, the Victrix Guard advance fearlessly into battle with their Bolters thundering and their heads held high. At their head strides a band of Ultramarines Honour Guard led by none other than Cato Sicarius, the hot-blooded master swordsman of Talassar. A true gathering of courageous heroes, the Victrix Guard are more than capable of cutting their way through entire armies of foes, heaping their bodies in gory mounds for the enduring glory of Ultramar and the ever-lasting realm of the Emperor Himself.
Through the course of the Crusade, Sicarius' combat prowess and unwavering faith aided the Imperial forces of the Crusade in all their trials and tribulations in the Warp rift known as the Maelstrom, where they had been cast by a great sorcerous ritual cast by the Daemon Primarch Magnus the Red. While trapped within the Maelstrom the Crusade fleet came upon a world of black marble and bloody seas. They struck hard and fast against several strongholds of the piratical Renegade Space Marines called the Red Corsairs, eliminating outlying enclaves before finally laying siege to a fortified palace upon a claw-shaped headland above booming, gory waves. While Archmagos Cawl coordinated the siege, Greyfax and Sicarius led a daring raiding party that threw open the palace's main gates and sealed the Heretics' doom.
The survivors of the Terran Crusade finally arrived in the Sol System at Luna through the Webway after being freed from imprisonment in another Blackstone Fortress belonging to the Red Corsairs. Following the Crusade's rescue by the Fallen Angel Cypher and a troupe of Harlequins, Sicarius was one of the few Imperials to survive the Terran Crusade. After aiding in the defeat of the forces of the Thousand Sons Traitor Legion and the Magnus the Red on Luna, Sicarius and her allies were finally ferried to the Imperial Palace on Terra.
There, before the Eternity Gate of the Inner Palace leading to the throne room of the Emperor where Guilliman would meet his father for the first time in ten standard millennia, Sicarius took up his post with the Victrix Guard to await their master's return. Guilliman emerged a solar day later from the Palace and was soon restored to his former position as Lord Commander of the Imperium. As Guilliman prepared to launch a massive counteroffensive against the gathering forces of the Ruinous Powers known as the Indomitus Crusade, there was no doubt that Cato Sicarius and his fellow Battle-Brothers would stand at their Primarch's side and face the enemies of the Emperor.
Cato Sicarius is known to wear a special suit of Artificer Armour known as the Mantle of Suzerain that provides a level of protection equivalent to that of a suit of Terminator Armour. The left pauldron of this armour belongs to the original suit of Mark II Crusader Power Armour worn by Captain Orar, a great hero of the XIII Legion during the Scouring of the Traitor Legions from Imperial space after the end of the Horus Heresy and a former Captain of the 2nd Company. It bears the 2nd Company's heraldic colours which Sicarius has also adopted as his own personal heraldry and also incorporates an Iron Halo and a Golden Aquila that designates his position as the Grand Duke of Talassar, his homeworld. Sicarius' helmet is topped by a transverse Valour Crest that was granted for near-suicidal acts of bravery during the nine-solar-day-long battle fought for control of Fort Telendrar. The colours of the crest match those of the Talassari noble house from which Sicarius was recruited as an Aspirant into the Ultramarines many standard centuries ago. Sicarius prefers to wield a potent relic Power Sword known as the Talassarian Tempest Blade in close combat. An ancestral relic, the weapon's energy field is so potent, and the blade within possesses a legendary sharpness so keen, that it has slain many a mighty foe in but a single stroke. Complementing this close combat weapon, Sicarius also wields an Artificer-crafted Plasma Pistol.
- Aquila - The Aquila is an Imperial Honour Badge shaped in the form of the Imperium's own crest that proclaims its wearer's great wisdom. It was awarded to Sicarius at the commencement of the Dantaro Campaign, which represented Sicarius' first action as Captain of the 2nd Company.
- Eternium Ultra - There are few such revered relics in the Realm of Ultramar as these gardbarces. They mark Sicarius as the High Suzerain of Ultramar and defender of the eight systems of Ultramar.
- Imperial Laurel - This Imperial Laurel was awarded to Sicarius in the wake of his service in the Crusat Minor planetstrike of 733.M41.
- Honorifica Valourum - Awarded in recognition of exceptional bravery when fighting Orks during the Battle for Dyzanyr.
- Personal Heraldry - Sicarius' left shoulder plate originally hails from an ancient suit of Mark II Crusade Pattern Power Armour worn by the Ultramarines Legion hero Captain Orar during the Great Scouring of the early 31st Millennium. The heraldry combines the Iron Halo, the Ultramarines Chapter icon and the golden Aquila that marks Sicarius as the Grand Duke of Talassar.
- The Valour Crest - The right to bear a crest upon one's helmet in the Ultramarines Chapter must be earned through acts of near suicidal bravery. Sicarius won his crest during the nine-solar-day long battle for Fort Telendrar. The colours of the crest are those of the Ultramarran noble house from which Sicarius was recruited, countless decades ago.
- Victorex Alpha - This honour, attached to Sicarius' combat skirt, was granted in recognition of his exceptional valour during the Siege of Rynneth V.
When Marneus Calgar travelled to Talassar after M'kar the Reborn's attack upon the Realm of Ultramar in 999.M41 during the Invasion of Ultramar campaign, the Codex: Space Marines (5th Edition) makes clear that Calgar accompanied Sicarius and the Ultramarines 2nd Company to that world. However, in the novel The Chapter's Due by Graham McNeill, Calgar travels to Talassar with the Ultramarines 1st Company led by Captain Severus Agemman. The 2nd Company did not arrive at Talassar in the novel until first concluding their own campaign against the Forces of Chaos on the Cardinal World of Espandor.
This was later explained away by the Black Library that Games Workshop maintains multiple different canons in the Warhammer 40,000 universe and that the only truly official canon is found in the various Codexes.
- Codex: Space Marines (6th Edition) (Digital Edition), pp. 82, 97, 346-349
- Codex: Space Marines (5th Edition), pp. 19, 22, 40, 85
- Warhammer 40,000 Rulebook (5th Edition), pp. 18-19, 22, 36-40, 85, 129
- Warlords of the Dark Millennium - Sicarius (Digital Edition), pp. 3-4, 7-12, 19-24, 27
- White Dwarf 345 (UK), "The Battle for Black Reach," by Phil Kelly, pp. 52-79
- White Dwarf 317 (UK), "Medusa V Campaign"
- Assault on Black Reach (Novel) by Nick Kyme
- Fall of Damnos (Novel) by Nick Kyme
- Apocalypse: War Zone Damnos (6th Edition), pp. 7-24