‘How dare you!’ Fulgrim screamed, rearing back. He lunged at his enemy and crashed bodily into him, knocking Guilliman from his feet. The Invictarus Suzerains thundered down the steps to join their lord, forming a shield wall about him as he scrambled up, but Fulgrim slithered into them, barging them from their feet and slaughtering them contemptuously, his swords lopping limbs off with every strike.

‘You will die!’ shouted Guilliman, and he surged past his last bodyguard as Fulgrim’s swords punched through the Space Marine’s shield, armour and body. He swung hard with his gauntlet, but Fulgrim was too quick and weaved to the side; the Hand of Dominion punched down and into the marble steps, pulverising three of them.

Guilliman span around, anticipating Fulgrim’s next strike, but the daemon had gone.

He searched for his brother in the conflict. Their two armies had met, and their struggles filled the Heliopolis side to side. His warriors and the Emperor’s Children were intermingled, the blue armour of the Ultramarines dotted within a sea of clashing colours and battleplate decorated with the stretched skins of the dead. Cones of sound visibly tortured the air, blasting Guilliman’s warriors from their feet. Blood fountained from breathing grilles as dying Space Marines coughed up shattered internal organs. A knot of white-helmed Terminators stood back to back, dealing death to any traitor that strayed near, while a wall of Ultramarines Second Company brothers advanced, guns booming, pushing back insane warriors.

War was everywhere, desperate and wild. The situation in the void was mirrored within the Heliopolis. His men were outnumbered. They would die.

First theoretical, Guilliman thought. Fulgrim is a prime evil in this world. First practical, I will kill him.

Second theoretical, he countered, you are angry. Second practical, you will throw your own life and those of your men away for nothing. You have failed in this campaign. Retreat.

A memory of Konor Guilliman, his adoptive father, flashed in his mind.

‘Control your humours,’ Konor had told him. ‘You are mightier in every regard than any man, and that includes your passions. Master them, or you will fail.’

Temper. There was always his temper. For most of his life, Roboute Guilliman had kept his emotions in check, but there had been notable occasions when he had lost his head. At Calth, and when Sotha was attacked. Or when he had arrived late to Terra. Or the early days of the Scouring… He would add this day to that record. Beneath his commanding exterior, Guilliman was seething with fury.

‘Fulgrim!’ he bellowed. ‘Face me!’

A whip-fast motion flickered to his side. Fulgrim sped through the melee, coming from the left. Guilliman barely had time to raise his sword before Fulgrim crashed into him, snarling incoherently, knocking him backwards.