The Emperor Falls.

Part 3/? - Accept your fate, begin anew!

Sanguinius lands upon the ship's back ramp, separated from the group. He begins moving inward, noting the daemonic presence and biting jaws of Chaos he can feel snapping at his heels. He rushes forward, hearing screams, human in nature. Marines trapped within hands coming from the walls. He slashes at them, freeing them before leading the men to the command room. There, he sees him. The reason this heresy had unfolded.

Horus Lupercal. The Chosen Son and Warmaster of Chaos Undivided stands at the command deck's window, viewing his victory in malicious pleasure and pride, as Terra burns. Sanguinius shouts, a voice of divinity and fury bellowing out, "Horus! Face me down you coward! You have run for long enough."

Horus laughs before charging him. Weapons clash, the Telestian Spear clanging against the Warmaster's Worldbreaker. It is a battle of wits as much as strength. The Spear slams into the Warmaster, a dent formed in his armor. He shrugs his hit off and slams the Worldbreaker into him. As he feels death calling he charges the Warmaster and is again knocked to the ground. He hears Horus cackle out "Accept your fate or begin anew! At my side!" However he takes no notice as he begins to change. A fury imbued within his soul and mind that has permeated in all his men. The Black Rage. His wounds slowly heal and he is about to charge him. "I will never stand by you!" He rushes at Horus, spear at the ready when he suddenly feels cold and weightless, as if he was in some sort of void. 

He is no longer on the ship, but in the Warp. He hears a strange voice from beyond calling to him. "Accept your fate and  begin anew!" He is dropped upon a warp ridden land scape. He looks up and sees him there. Horus and the Emperor? The Black Rage brews as he sees Magnus crushed within the traitors hands, feeling a burning at his mind and soul that he finally gives into. With that last wall of resilience falling, he cares no longer for whatever foe stands ahead and he charges. Horus isn't even able to drop Magnus in time before the Spear breaks through Horus' armor, the same dent that just seconds ago was struck in his armor aboard the Vengeful Spirit now trapping Sanguinius' spear. 

Horus cackles, realizing that Sanguinius is stuck, his spear unable to be removed just as Dorn had struck down his mysterious brother upon the planet of Pluto. He raises the Worldbreaker, before hearing the crackle of the Spear. "Horus!" Alpharius shouts as he sees Sanguinius' spear charging, realising he is too late to save his brother from his own folly. Just before he can swing down, the spear blows a massive hole through Horus' and as he collapses onto his knees, ready for death Tzeentch sends him through a warp portal, back to die upon the Vengeful Spirit at the same man's hand who stands before him now.

The Emperor stands, questioning Tzeentch, attempting to reason with himself at why he intentionally weaken himself by adding one of his strongest sons to the field. Tzeentch answers quickly, through Sanguinius and his spear no less.