Blood Angels - Siege of Terra: For all the might of the Emperor, for every effort of Sanguinius and the remaining Loyalist Primarchs, the forces of Horus drove all before them. In too short a time, the Emperor of Mankind was assailed within His great Imperial Palace on Terra. Fortunately for the Loyalist forces, the Blood Angels were present for the titanic final battle of the Horus Heresy, the Siege of Terra.The Blood Angels, Imperial Fists and White Scars defended the Imperial Palace with zealous fervour. Sanguinius himself led the defence of the outer walls. Three times the Warmaster's troops gained footholds on the walls, and three times they were driven back by Sanguinius and his Blood Angels. When the wall was broken by attacks from Chaos Titans, Sanguinius organised the retreat to the Inner Palace. At the Eternity Gate, the entrance to the Emperor's throne room, Sanguinius defied the Chaos horde long enough to buy time for the Loyalist wounded to be carried inside.As the last were carried in, Sanguinius went to return to the Palace. Before the Eternity Gate could shut, Ka'Bandha, Arch-Daemon of Khorne and Lord of all the Bloodthirsters, attacked the Primarch. The Angel and Greater Daemon fought in the air over the Imperial Palace, but Sanguinius, weary and taken by surprise, was cast down. Ka'Bandha hovered in the air, laughing gutturally at his opponent's despair. Sanguinius, however, was not dead. Sanguinius regained his senses, and took to the air. Flying as swift as a missile, the Primarch seized the daemon's ankle and lifted it high into the air. Before the daemon could bellow its fury, Sanguinius broke its back over his knee. He hurled the carcass back at the Chaos horde, who howled in fury. The Eternity Gate was closed.When the imminent arrival of the Space Wolves, Dark Angels and Ultramarines Legions forced Horus to gamble on forcing a final battle with the Emperor by dropping the Void Shields protecting his Battle Barge, the Vengeful Spirit, Sanguinius, Rogal Dorn of the Imperial Fists, and the Legio Custodes joined the Emperor in a daring teleport assault upon the vessel. The Chaotic sorcery protecting the ship scattered the Loyalist strike force throughout the vessel after they teleported. Only Space Marines could have withstood the horrors of that Daemon-haunted starship, and even they were sorely pressed. Sanguinius was swiftly separated from his comrades and, so the legend tells, was brought through artifice before the treacherous Horus. As Sanguinius possessed the psychic ability of foresight, it seems almost certain that he knew he was going to his death. It remains unknown whether fatalism or loyalty brought Sanguinius aboard. The Blood Angels themselves have no doubt on the matter.The two Primarchs and former brothers finally met on the command deck. In evil cunning, Horus offered Sanguinius a position of power if he would renounce his loyalty to the Emperor, and Sanguinius refused. Thus rejected, Horus flew into a rage and attacked. Even at the peak of his powers Sanguinius could not have hoped to prevail against the monster Horus had become, and the Primarch was weary and wounded from his travails on Terra. Despite his grievous wounds, Sanguinius managed to match Horus' martial prowess, even at the height of his daemonic power, and Horus was forced to deal with the Angel by psychic methods.In his limitless malice, Horus made sure that Sanguinius' death was the most painful and foul that the boundless evils in his service could administer. The Warmaster's psychic assault was so powerful, it echoed down through the generations of Sanguinius' sons who are haunted by its echo within their souls to this day. When the Emperor at last entered Horus' sanctum, he found His rebellious Warmaster standing above Sanguinius' broken, bleeding corpse. In the battle that followed, Horus was finally vanquished, though the Emperor too was cast down near to death. There are many tales told of this final battle and, though the exact facts are long lost, one detail holds through all the recitations through all the millennia since. Despite the Emperor's great power, he could never have bested Horus had not the blade of Sanguinius wrought a chink in the Warmaster's armour, and because of this, the Blood Angels claim him to be the greatest of the Primarchs.