The Emperor against Horus (Vengeful Spirit)

Entering the throne room of the Vengeful Spirit and seeing at the feet of Horus the winged corpse of Sanguinius, the Emperor met his fallen son in a duel across matter and the immaterium. Full of the power of the Four, Horus overpowered the Emperor, but at the decisive moment, sure of victory, he cast off the warp-power to finish his Father as a mere primarch; the Four would not give it back — and the Emperor incinerated the soul of Horus, erasing him from existence. The victory cost the Emperor mortal wounds: broken and fading, he will be carried by Dorn to the Golden Throne.