Among the loyal primarchs still walking the world, Sanguinius possessed the deepest understanding of the Warp.
He understood what The Emperor was doing. The Emperor was soothing the human souls accumulated within him, souls that had soaked alongside him upon the altar of the Dark King. Most had already been destroyed, permeated by dark, frigid emotions. What The Emperor was doing now was trying to use the living to awaken those souls not yet completely submerged by the Dark King, to awaken their humanity, to awaken those beautiful, pure emotions.
The Emperor could draw humanity from them, learn humanity from them, reshape humanity through them, improving his own condition, resisting the pressure of the Dark King more effectively, and better withstanding the pressure the Machine God would soon bring down.
Guilliman encountered his mother and father. Fulgrim was facing the judgment of his descendants. In the distance, Lena saw her mother. Countless Astra Militarum soldiers saw their departed loved ones, while many Astartes saw the brothers who had fallen before them.
Sanguinius pursed his lips, his golden eyes fixed awkwardly on the man before him.
He had imagined seeing his sacrificed sons, the tribes of Baal that had raised him, and the devout believers who worshipped him.
But the instant he saw that gleaming bald head, Sanguinius had to admit he felt an urge to immediately take the Crimson Tear to Terra, land at the Gate of the Lion spaceport, pass through the Gate of the Lion to stand before the Golden Throne in the Sanctum Imperialis, climb the one hundred and thirteen steps, and kick that mummy's little toe.
It was not as though he did not want to see him.
True, he had killed Sanguinius, painstakingly hammering him into a pulp blow by blow.
But... Sanguinius also understood