The Blood Angels are one of the 20 First Founding Legions of the Space Marines and were originally the IXth Legion before the Second Founding broke the Legiones Astartes up into separate Chapters of 1000 Space Marines.
Sanguinius, also known as the "Great Angel" and the "Brightest One" during his lifetime, was the Primarch of the Blood Angels Legion of Space Marines. Sanguinius is noted for his giant angel-like wings which are result of a mutation during his childhood on Baal. He was one of the greatest primarchs and thought to be second in choosing for a Warmaster from the Emperor, after Horus. He was killed during the climax of the Horus Heresy at the Battle of Terra defending the Emperor of Mankind from the Warmaster Horus aboard his flagship, the Battle Barge Vengeful Spirit. Though Horus slew Sanguinius, who had once been his closest and greatest friend amongst the other Primarchs, Imperial legend holds that it was the chink in Horus' armour created by the Angel that allowed the Emperor to slay the Arch-heretic and thus prevent Mankind from falling to the corruption of the Ruinous Powers of Chaos.
"For the Emperor and Sanguinius! Death! DEATH!"
The Blood Angels are one of the 20 First Founding Legions of the Space Marines and were originally the IXth Legion before the Second Founding broke the Legiones Astartes up into separate Chapters of 1000 Space Marines. They are well-known across the galaxy for their bloodthirsty nature in battle, and feared for the curse of flawed gene-seed they carry. The Blood Angels are amongst the longest-living of the Adeptus Astartes, with some of the Chapter's Space Marines having served the Emperor of Mankind for over a thousand standard years. Due to recent events, the Blood Angels' numbers were severely depleted. Under the threat of extinction, and in order to quickly replenish their numbers, the Blood Angels were forced to ask their kindred Successor Chapters from subsequent Astartes Foundings for a tithe of warriors from the related Chapters' pools of Neophytes, their candidate Space Marines. With these tithes of new recruits, and the recent arrival of the Primaris Space Marines during the Indomitus Crusade, the Blood Angels were able to replenish their losses, though they still face a time of trial like none the Chapter has known since the days of the Horus Heresy. The Blood Angels are the noble descendants of that most puissant and angelic of the Primarchs -- Sanguinius. They are perhaps one of the most celebrated Chapters in the entire Imperium, their countless heroic deeds and victories known to untold billions of the Emperor's subjects across the length and breadth of the galaxy. The beauteous, angelic visages of the Chapter's heroes adorn Gothic facades and stained glass windows in a million holy basilicas, and their portraits gaze serenely from endlessly copied and much cherished illuminated tomes.
Yet, hidden from the multitudes, the Blood Angels harbour a terrible curse. When their beloved Primarch was slain at the hands of the Arch-traitor Horus at the very height of the Horus Heresy, every Blood Angel was doomed to share a portion of the pain inflicted upon his flawless form. From that day forth, every Blood Angel has been tormented by visions of the last moment of Sanguinius. The older the Space Marine gets, the more frequent and debilitating such waking nightmares become. Should he not fall in battle, every Blood Angel will one day become so consumed by these soul-searing visions that he will descend into a madness in which he must witness the death of Sanguinius over and over again, ever unable to intervene as the Warmaster enacts his vile treachery. The very inevitability of their curse ennobles the Battle-Brothers of the Blood Angels, driving them ever onwards to a glorious death in the name of the Emperor and their Primarch. Where lesser men might have surrendered to the dark urgings to shed the blood of the enemies of the Emperor, the Blood Angels have remained pure and noble for ten thousand standard years. Despite this, the Chapter is dying, for each year ever more of its brethren succumb to the so-called Red Thirst -- the desire to rend limb from limb those responsible for the death of Sanguinius, and by extension every enemy of the Emperor. The death of Sanguinius represents one of the most perfidious and tragic moments of the Horus Heresy, for he died at the hands of his brother-Primarch, the Arch-traitor Horus. Although some say that the sacrifice weakened the Warmaster just enough to allow the Emperor to later defeat him at the climax of the Battle of Terra, the death of Sanguinius is mourned to this day, and felt keenly by the Blood Angels, in whose veins his blood still pumps. When war calls and blood is spilled, the Blood Angels are gripped by a fury born of the last moments of their Primarch's life. For some, the thirst is too great and they are entirely overcome by what is called the Black Rage, cursed to end their days reliving their beloved Primarch's death over and over again.
The beatific Sons of Sanguinius are known and celebrated across the Imperium, representations of the greatest heroes of the Blood Angels carved in marble, painted in oils, and sewn in tapestries in a million cloisters and more. Their angel-winged Primarch is an object of veneration on countless worlds, his perfect visage gazing down on the faithful with a mixture of benevolence and pity. The Blood Angels are the inheritors of Sanguinius, and they bring death from above to the enemies of the Emperor. The Chapter seeks the beauty of perfection in all it does, and in one particular field of warfare surpasses all other practitioners. While all Chapters of the Adeptus Astartes are masters of the Drop Pod and Thunderhawk assault, the Blood Angels have become synonymous with the flawless execution of the aerial assault. They employ an entirely new pattern of vehicle of mysterious origins: the Stormraven gunship. This vessel appears as a lighter cousin of the Thunderhawk, and while its smaller size means it carries less weaponry and a smaller troop capacity, it greatly makes up for this in speed and manoeuvrability. While the Adeptus Mechanicus took several standard centuries to examine and debate the use of the Standard Template Construct imprint of the gunship, the Blood Angels saw its worth immediately, and set about introducing it into their armoury. Lately, the Chapter's Forge has been able to perfect its fabrication methods to such an extent that the gunship is now being used throughout the entire force. While the gunship is only just beginning to enter service in other Astartes Chapters, the Blood Angels are already masters of its use, and they have refined methods of aerial assault others are just beginning to learn. The Blood Angels' doctrine of aerial assault culminates in savage close combat. Whether they are delivered into battle by Thunderhawk or Stormraven gunship, or in the troop bay of an armoured transport such as a Rhino, Razorback or Land Raider, the Blood Angels are all but peerless in their mastery of close assault. This is in part because the gene-seed of Sanguinius grants his sons an incredibly long life span even for Space Marines, during which endless solar hours of practise and countless battles hone their skills to perfection. Yet, the Blood Angels are not driven towards the fury of close assault by tactical necessity or battlefield doctrine alone
The Chapter's reliance on blood and the need to cleanse it to keep the Flaw at bay exerts a strange and all but irresistible hold on the Blood Angels. In battle, the Blood Angels are drawn to spill the blood of their foes, and their ordinarily noble countenance can occasionally transform into twisted, rage-fuelled masks of savagery. This is referred to as the Red Thirst, and it is something that every Blood Angel experiences. For many, the Red Thirst is prelude to the ultimate expression of the Flaw, the Black Rage, in which the state becomes permanent and all-consuming. The Blood Angels and their Successor Chapters are unique in that their gene-seed imposes an unusual, and ultimately tragic, flaw upon each Battle-Brother. For most Chapters, service begins as a Neophyte, with the Initiate becoming ever more senior the more battles he survives until the few that remain are granted command of a company, become a specialist such as a Chaplain, or even become Master of the Chapter itself.
The Blood Angels experience an entirely different journey, though few outside of their ranks ever learn of it. The Blood Angels possess an almost supernaturally noble, almost saintly countenance, their features handsome and pure. This is all the more amazing because the Chapter recruits from the short and stunted men of the tribes of Baal, riddled with stigmata, lesions, and carcinoma caused by radiation poisoning. Their dramatic transformation into the saintly Neophytes is only made possible by arcane bloodrites. Over a lifespan far longer than that of the average Astartes, the Blood Angel hones his skills, yet with each battle he experiences something more of the Flaw, the urge to spill the hot, steaming blood of his foes growing ever stronger. As it does so, the Battle-Brother is driven to spend longer periods of time purging his own bloodstream within the crimson embrace of his transfusion casket. After several standard centuries of service he must spend long solar hours within it, having every drop of his own blood scrubbed clean. At some point, the Blood Angel is likely to feel the stirrings of something deeper, the rage descending not at the culmination of battle but before it. These are the first echoes of the Black Rage, and while most Blood Angels fall in combat long before succumbing to it, those who cannot hold it at bay are forced to enter the infamous Death Company.