Warhammer 40k: Blood and Blades

Prologue- An Angel Falls

Sanguinius beat his mighty wings, taking flight against Warmaster Horus as he waved his Black Mace in futile attempts at swatting the Loyalist. The Primarch of the IXth Legion hovered for a moment, staring at the Traitor. "You were my Brother!" Sanguinius cried. A nimbus of light played about his head.
The Traitor bellowed a malicious guffaw. "Yes. You respected me, trusted me, believed me." He extended his arm. "You can do so again, Brother."
Sanguinius' eyes flashed. "I shall not fall prey to the Ruinous Powers of Chaos!"
The Warmaster growled, his Dark-Forged Terminator Armour glowing fiery red. "You truly are an Angel. Then it is time to cast you down! The Imperium itself will be set upon by the Dark Gods! The so-called Emperor of Man shall be entombed in the very ruins of his great palace!" He smiled. "And you will never end the plague of which affects your flock."
Sanguinius grasped his greatsword, a large blade half as long as his ten-feet-tall self, preparing to continue the fight. "Blasphemer!" he shouted, and rushed to meet his old friend in battle.
Horus gave a mighty swing, yet missed. The Angel landed with such force, the Warmaster was nearly felled. He set to swinging, but the Traitor anticipated the strikes, side-stepping each one.
Both Primarchs were heaving, yet neither were willing to back down.
"Don't you see?" Horus grumbled. "This War is madness. With our combined efforts, the Imperium will shatter. You will be a God among mortals. Our father would bow at our prescense. Will you not join me, Brother?"
"You are no Brother of mine. Not anymore." He spat.
Horus managed a clumsy swing, blind with anger. It smashed a glancing blow on Sanguinius' crest, cracking the heart-shaped stone in the breastplate. The Angel retaliated, slashing at the Warmaster full of zeal. A chink was wrought in the Traitor's armour.
The Betrayer flew into a frenzy, trading blow for blow with his old friend. He gained the upper hand, smashing the IX Legion Primarch over the head.
From there, the Warmaster set about granting Sanguinius a painful end. He took to his mace once again, slamming it down upon the Angel's broken body.
As Sanguinius lay there, the chamber went awash with a great light, the source at the archway.

Horus smiled, displaying ragged fangs. He was utterly consumed with madness. "Father!" he shouted, lowering his mace. "You finally arrived. Now you understand your race to save Terra, and all of Mankind, has been for naught."
The Emperor's face was of steel. "You... You are no Son of mine."
Horus raised his bolter, and struck his father in the chest. The Saviour of Mankind wavered, clutching the wound.
"Long have I awaited those words." Horus growled. "You never loved me. Your sons were but pawns. So long as-"
In Sanguinius' final moments, he watched his brother and father do battle, the Emperor striking Horus in the very chink Sanguinius created. A final service to his father, he had long known; his pure heart had gifted him with foresight. This gift had aided him and his own 'children' in the Great Crusade for Humanity. Though in front of him the Emperor, despite His grevious wound, is doing battle with His Psyker abilities against Horus' own, in the back of his mind, he witnessed his Legion, all slathering and snarling for blood, donning Armour of Mourning. High above them, he flew, driving them onwards, yet he was without the Black Armour. At the helm was his father, the Emperor of Mankind.
The world was a blur now, though the shapes of his father and brother ceased their dance of death, the dark form of the Warmaster gasping for breath. His voice resonated throughout the samctum. "You wouldn't kill your favoured son, would you?"
The Emperor's face was flushed, yet determined. "My favoured son died long ago." A single flash ended Horus' existance. Only then did Sanguinius close his eyes for the final time.