World Eaters - Siege of Terra: By the time the Siege of Terra commenced, Angron had become fully enslaved to the will of the Blood God Khorne and his own unquenchable blood lust. He demanded that Horus allow him to directly assault the Imperial Palace, regardless of the fact that the Emperor's powerful psychic barrier around the Throneworld would more than likely kill the Daemon Prince until the Traitors had found a way to weaken it.When word reached Angron that the Death Guard would instead be the ones to spearhead the Traitor assault on Terra, Angron fell into an incandescent rage and massacred all those within the bowels of the Conqueror who had the misfortune to cross the Daemon Primarch's path.Lotara Sarrin, the mortal Human captain of the Conqueror, feared that if Angron wasn't stopped, he would inadvertently murder the Tech-priests responsible for attending to the vessel's Plasma Reactor, putting the Conqueror at risk of a catastrophic explosion.To prevent this, Sarrin conspired with the Night Lords Captain Gendor Skraivok, the "Painted Count," as well as Khârn, to have Angron teleported to the shifting maze aboard the Night Lords' flagship Nightfall that had long been used by Konrad Curze to torture and kill captives. Forcing Khârn's hand, the Eighth Captain confronted the enraged Daemon Primarch himself.Angron informed his Equerry that the Dark Gods had whispered to him of Khârn's ultimate fate and pre-ordained destiny as the Chosen of Khorne. The Daemon Primarch wished to supplant Khârn as the Blood God's chosen, and so, the two battled one another.However, Khârn proved unable to match his gene-sire's prowess. Before Angron could slay him, Khârn placed a Teleport Homer on the Daemon Primarch and had him teleported off the Conqueror and into the bowels of the Nightfall.In the bowels of the Night Lords' flagship, Angron found himself trapped within a labyrinth of singular purpose. At the request of the Night Haunter, the Iron Warriors' Primarch Perturabo had crafted his grim brother a singular prison, unlike any other, in imitation of Perturabo's own private sanctorum known as the Cavea Ferrum.This special prison was an elaborate labyrinth, whose featureless walls and strange geometric design made it all but impossible to map and therefore escape. Anyone who attempted to mentally map the labyrinth would be hopelessly knotted in turns that should have been physically impossible.Even after trying scores of times to map the labyrinth, an individual would only manage more than a handful of turns within its twisting corridors before it all stopped making sense. Following the Drop Site Massacre of Istvaan V, the Night Haunter had captured his brother Vulkan, the Primarch of the Salamanders, and utilised the labyrinth as a means to torture and psychologically break him over a period of several solar months.Angron quickly became trapped within the maze, forever trying to find his way out of its twists and turns, and battling assaults by the multitude of traps hidden within the labyrinth.Meanwhile, the Traitors on Terra's surface had used a series of rituals to finally weaken the Emperor's psychic barrier around the Throneworld so that they could deploy their daemonic allies on its surface. The Daemon Primarch was shot from the hold of the Nightfall and into the void of space. Angron soon hurtled towards the Throneworld's surface.When the Daemon Primarch entered Terra's atmosphere, he appeared as a massive, flaming meteor. As his body slammed into the surface of Terra, the shockwave of the Daemon Primarch's impact slew friend and foe alike.Wielding the Black Blade, Angron proceeded to rampage through the Loyalist forces, fighting his way to the walls of the Imperial Palace itself. Here, he saw his brother Sanguinius, the angelic Primarch of the Blood Angels, and bellowed a challenge. In response, Sanguinius merely saluted his brother and refused. Before withdrawing back into the confines of the Imperial Palace, Sanguinius claimed that while they would one day battle, it was not that day.The Daemon Primarch roared in frustration, unable to circumvent the lingering effects of the Emperor's psychic barrier to pursue what he perceived as his cowardly brother into the palace.As the Siege of Terra raged on, during the battle for the Lion's Gate Spaceport, Angron destroyed both a Capitol Imperialis super-heavy Imperial tank and then a Leviathan transport, but was still unable to advance past the Imperial Palace's walls.But eventually, the Lion's Gate Spaceport fell to the Traitors when they launched a massive assault. As the Emperor's psychic barrier shrank to encompass the Sanctum Imperialis, Angron led a horde of blood-maddened Worlds Eaters onto the Eternity Wall and began slaughtering the Loyalist defenders.Newly blessed with daemonic gifts, Angron and his World Eaters overtook the Loyalist defenders of the Eternity Wall. Later, the World Eaters had the duty and privilege of leading the frontal assault on the palace. The surviving video logs from the siege show the World Eaters breaching the walls of the palace, the twisted, red form of Angron wielding his glowing runesword at their head.Among those first into the breach was Khârn. Despite contrary claims by the Sons of Horus, World Eater records indicate that it was Angron's daemonic Black Blade that was responsible for the downfall of the great gate of the Imperial Palace.The World Eaters reaped a true harvest of blood on Terra, but they were denied ultimate victory. With both the Dark Angels and Space Wolves Legions on their way to Terra to reinforce the Loyalist defenders, Horus gambled everything in order to win the siege, lowering the Void Shields on his flagship, the Vengeful Spirit, and daring the Emperor to come aboard and face him.The Master of Mankind rose to the challenge and faced his betrayer in the combat that decided the fate of the galaxy. The two fought a titanic combat that was both physical and psychic, until at last the Emperor had slain Horus and utterly obliterated even his soul from existence, but only at the cost of His own humanity and eternal internment in the Golden Throne.The mighty Chaos army disintegrated with the loss of its greatest champion and fled Terra. Angron was the last to leave, looking back from his drop ship longingly at the Imperial Palace, which had stood against even his fury.He led his surviving World Eaters deep into the refuge of the great Warp rift that was the Eye of Terror in the northwestern reaches of the galaxy. He and his Heretic Astartes would now have all of eternity to seek revenge as part of the Long War against the Corpse Emperor's forces to come.With the Horus Heresy ended, the World Eaters fled into the Eye of Terror to a Daemon World specially prepared for Angron by Khorne, though the Legion swiftly degenerated into roving warbands of Chaos Space Marines as the incessant and bloodthirsty demands of Khorne drove the World Eaters to turn in upon themselves.As such, even to the present time they have no particular home base, with each band generally operating from whatever starship they can lay their bloodstained hands upon.