When the Emperor began his Great Crusade to reunite the galaxy he created the Primarchs, superhuman warriors to lead his Space Marines across the galaxy. The powers of Chaos stole the Primarchs, but unable to destroy them, set them astray in the Warp [Needs Citation].
The infant Sanguinius came to rest upon the moon of Baal Secundus and was adopted by a tribe of humans known as the 'People of the Pure Blood' or simply 'The Blood', Sanguinius, like all Primarchs, grew quickly and soon surpassed all his teachers and was capable of mighty feats of strength and endurance. Uniquely amongst the Primarchs he sported a pair of angel-like wings from his back, though whether this was by the design of the Emperor or a mutation caused by the high levels of radiation on Baal is unknown. He was also said to have psychic powers, especially the ability to divine the future[Needs Citation].
Sanguinius was able to foresee the Emperor's arrival on Baal and the two met upon the surface. Sanguinius bowed his knee before the Emperor and pledged his service to the Imperium, unlike resistance from some of his brothers like Leman Russ. The Emperor had already created a Legion of ten thousand Space Marines using Sanguinius's gene-seed and thus the Blood Angels were finally united with their Primarch[Needs Citation].
The Great Crusade
During the Emperor's Great Crusade, Sanguinius and Horus became close brothers and it was said that they were closer than any of the other Primarchs. Supposedly Horus pointed to Sanguinius to be the new Warmaster when he thought he was dying on Davin. He provided counsel that Horus listened to during the incident with the Interex, shortly after Horus became Warmaster and was generally the one with the most sway on Horus, after the Emperor[Needs Citation].
Sanguinius was a beloved figure who was revered by all of the Imperium. The noble angel was highly respected by all the legions, and by all his brother Primarchs. Even Horus highly valued his brother's advice. It was Sanguinius who convinced Horus to follow the Emperor's suggestion and rename his legion. As Horus lay dying above the planet Davin, he revealed that he believed Sanguinius should have been proclaimed Warmaster in his stead[Needs Citation].
Before Horus' treachery was revealed, he sent Sanguinius to a world named Signus Prime. There he was ambushed by hordes of daemons, badly damaging his Legion, with a Greater Daemon of Khorne named Ka'Bandha even managing to wound the Primarch himself by breaking his legs. Eventually they succeeded in beating the daemons back and withdrew to Terra [Needs Citation].
In the Battle of Terra, Sanguinius fought valiantly, organising the final defence of the Imperial Palace and held the Eternity Gate alone when no others could withstand the horror of the assault, even breaking the back of the same Greater Daemon Ka'Bandha who wounded him on Signum. When the Emperor teleported aboard Horus's Battle Barge, the Vengeful Spirit, Sanguinius was with him but they became separated and the Primarch was forced to face Horus first. Despite being in the pit of Horus's tainted and mutated Chaos fuelled Battle Barge, Sanguinius tried to revert his brother to the side of the Emperor, using their old friendship as a lever. Horus would not listen to or agree with any of Sanguinius' words and the two argued and tried to sway the other to the side of the heresy they stood upon. Sanguinius was eventually struck down by Horus, the only damage Sanguinius did was create a small dent in Horus' armour. Some say, however, that it was through this chink in Horus's armour that the Emperor was able to deliver the fatal blow. Thus the belief is that Sanguinius did not die in vain; but by dying, allowed Horus to be slain and the Heresy destroyed[Needs Citation].
Sanguinius's body was taken by the Imperial forces as they retreated from the buckling Chaos Barge and his body was borne away to his home planet Baal, where he was laid to rest in the Golden Sarcophagus, deep within a vast tomb whose doors were topped with massive Angel effigies in honour of the fallen Primarch. 
Of all the Primarchs, Sanguinius is commonly held in the highest honour. Because he is generally believed to have sacrificed himself to allow Horus, the "Great Betrayer", to be defeated, the Primarch's name is cherished by the common citizens of the Imperium. Temples devoted to Sanguinius rise aside those of the Emperor. Sanguinius is commemorated on a sacred day of celebration called the Sanguinala, when adepts across the galaxy wear on their breast the red badge of Sanguinius[Needs Citation].
- See also Quotes Space Marines
- Three Legions of Marines stand to defend you, sire. All of us will unflinchingly place ourselves between you and the war’s desolation. We are the greatest humans ever born – we are the flame of Humanity where the rest of the galaxy is just the spark. In centuries of warfare, against the vileness of the alien, the lies of the heretic, the foulness of the mutant, I have never known fear – but your silence terrifies me. - during the Battle for Terra[Needs Citation].
|I - Lion El'Jonson · II - Unknown · III - Fulgrim · IV - Perturabo · V - Jaghatai Khan · VI - Leman Russ · VII - Rogal Dorn · VIII - Konrad Curze · IX - Sanguinius · X - Ferrus Manus · XI - Unknown · XII - Angron · XIII - Roboute Guilliman · XIV - Mortarion · XV - Magnus · XVI - Horus · XVII - Lorgar · XVIII - Vulkan · XIX - Corvus Corax · XX - Alpharius Omegon|
- 1: Index Astartes II
- 2: Horus Rising (Novel) by Dan Abnett
- 3: False Gods (Novel) by Graham McNeill
- 4: Codex Imperialis
- 5: Red Fury (Novel) by James Swallow