Here's Guilliman vs Fulgrim in full:
'I hear you, Fulgrim!' he cried. 'Come out into the light!'
This time, Fulgrim replied. His voice was as mellifluous as it always had been, but the neediness that had always lurked at the back of his words had come to fore, a poison masquerading as confidence.
'Why are you in such a hurry?' he said, his whisper filling the Heliopolis. 'Your strategy is to play for time, is it not? To allow your sons in their fine new paints to cripple this ship. They look so colourful now, Guilliman, so much less dull than blue, blue, blue. How was it to break up your Legion, Guilliman? Did it hurt?'
'Come and face me. Let us settle our differences honourably.'
'Do you want to talk?' Fulgrim, still unseen, tittered. 'About what? A little family reunion? You and I have nothing in common. We never did, and now we have even less. I serve the true powers of this universe, while you languish under the dead hand of our father. You are so predictable, Roboute.' He laughed. 'So dull, so stolid. Boring old Roboute! You were the unloved child, while the brighter stars got all of father's attention. Overlooked, until the end, and then when you were needed you were not there. It must have stung, brother, to be so outshone. Perturabo did not enjoy it, I know. Did you?'
Guilliman peered hard through the light. It responded to his prodigious will, its obscuring effect lessened, and he caught a hint of sinuous movement on the far side of the circle.
'Our father honoured me always,' shouted Guilliman across the empty chamber.
Fulgrim laughed, louder and louder until the Heliopolis filled with wild mirth that seemed to issue from a thousand throats. 'Oh, forgive me! That is so precious. Do you not remember my eagle, dear Roboute? It was I who was honoured, not you.'
The rasping of scales drew closer. Luminous green eyes glinted on the other side of the inimical light. Guilliman set himself and stood tall.
'My Legion may not have won your plaudits, Fulgrim, but I chose the slow and steady road, and that was the better way. You were always racing toward perfection, away from your fear of failure. Your fear made you run right into the arms of damnation.'
'Failure?' Fulgrim scoffed. 'Damnation? I have not failed! I am not damned!' Fulgrim slithered into the light. 'I am saved.'
'For the love of Terra…' whispered Guilliman.
Guilliman had seen pict-captures of his brother from the siege of the Imperial Palace on Terra. He had viewed them many times, noting the changes wrought upon his sibling as dispassionately as he could, fighting back the revulsion he felt at the sight. Reports and the occasional image of his sibling had surfaced from his reavings since. The image on the Phoenix Gate had been no surprise. He knew what to expect, but faced with Fulgrim in the flesh, he struggled to contain his dismay.
The Phoenician's legs were gone, replaced with a long serpent's tail. His torso and face had become elongated, his chest altered to accommodate an additional pair of arms. Despite his obscene form, everything was weirdly perfect. The muscles in his bare chest were exquisitely defined. His skin was a gorgeous shade of lilac. The snakeskin of his lower half shone with jewelled colour, and he moved with grace to shame the aeldari. But all this was a perversion of his former beauty, if not of the very idea of beauty itself. It was too much, so perfect in its awful twisting of the human form that it went beyond the ability of the mind to process. Fulgrim's new shape provoked revulsion by its very nature, while awing with the artfulness by which it had been done. By design, he was made to arouse and repulse equally.
His head in particular was changed, long and crowned with horns that rose crimson from his shock of white hair. His face, however, remained his own, a sickening joke to crown his dark transcendence. Seeing the features of his brother melded to this monster brought tears to Guilliman's eyes.
Finely wrought ornaments jangled on Fulgrim's limbs. Soft leather straps held long gloves in place on his right arms. The left arms were painted with delicate patterns, his fingers hung with chains and their nails stained clashing shades. Vile sigils decorated the buckles of his harness. More were tattooed upon his skin.
Fulgrim rose up on his banded tail, holding his four arms wide in the sickly light of the Heliopolis.
'Behold, my brother. See! What the Emperor made, the Prince of Pleasure has improved upon. Am I not perfection? I was made to be a slave, but now I am free, and the companion to a greater god than our father can ever be.'
'The Emperor is not a god,' said Guilliman.
The ship quaked. A signifier in Guilliman's helmet turned from red to green. The portside void generators had been disabled. Datascreed informed him the Fourth Company of the Iron Snakes was making a fighting withdrawal.
'Do you still believe that?' said Fulgrim. He inched forwards, swaying hypnotically. 'He always did protest too much about that. You think I am a traitor, I know. You think I am selfish, and deluded, but no more so than dear, dear father. He gave me so much, not least a taste for treachery.'
Fulgrim leaned closer, close enough for his hot, perfumed breath to caress Guilliman's armoured face. The cloying stink of it penetrated his breathing grille, making him gag. There was a scent of something rotten beneath the melange of spices, one note of decay in a bouquet of opulence.
There is the truth, thought Guilliman. The miasma of corruption, a murdered corpse hidden in a bed of flowers.
'Join with me,' said Fulgrim seductively. 'You must be tired of all this strife. We can bring an end to war, and revel together in sweet excess for all eternity. I can show you things, pleasures, you would never have dreamed existed. You think of the warp as a hell, but it can be a heaven also. Together, we can usher in an age of delight for all mankind that will never end.'
'Never,' said Guilliman. 'You have been deceived. I will not follow you into darkness.' He stepped backwards, his hand going to the hilt of the Gladius Incandor. The primarchs were mighty beings and great in stature, but swollen with the power of Chaos, Fulgrim overtopped Guilliman by almost a metre.
'It is you who has been deceived, Roboute,' said Fulgrim.
'Look at what you have become, and you will see the wages of disloyalty.'
'You speak to me of loyalty.' Fulgrim tutted and shook his long warped head. 'And where do your loyalties lie, lord commander? You were late to the Palace, were you not? Delayed. Always, your love for your own kingdom trumps your so-called loyalty to our father. Like a little Emperor, playing at being daddy in the sand, making tiny empires. You would have saved the Five Hundred Worlds and lost the million of our father. Pathetic.' A long, forked tongue flitted over his painted lips. 'How are your Five Hundred Worlds now, brother? How many are left? Four hundred? Three? I hear Angron and Lorgar had a rare time bringing down the bastions of your puny realm and slitting the throats of your people.'
Guilliman's anger ran hot. 'I will not bend my knee to your masters. These gods you and the others profess to worship are not gods. They are monsters, nothing more. There can be no rapprochement between us. No reconciliation. You have become the tool of the enemy, and so I must kill you.'
'You have come to kill me? Really? How amusing, because I have come to kill you!' said Fulgrim with mocking surprise. He clapped his upper pair of hands. 'What a coincidence. You do realise, I need no starship to travel the void.' He gestured at his body, his four hands moving with obscene, suggestive precision. 'I am no longer a thing of this realm of ash and dust, but a radiant creature of the warp.' He pulled a moue of sympathy. 'Oh, I am so sorry, but this was a trap for you, Roboute ― the whole thing, from my first raids to your supposed victory at Xolco, and you have fallen into it.'
Since the first indication of Fulgrim turning to fight here, Guilliman had known he had been outplayed, but he would not give his brother the satisfaction of knowing this. He steeled his heart and prepared to fight.
'I will not be turned.'
'I never thought you would,' said Fulgrim sweetly.
Another shudder passed up the Pride of the Emperor. The rune denoting the strike against the enginarium turned green. Corvo would be pulling his Chapter back.
'You can run now, if you want,' said Fulgrim. 'I believe your warriors have accomplished what you sent them to do. This vessel cannot pursue you. Some of you might even live. I do not care. All of you will bow before Slaanesh before the end.'
'Enough!' said Guilliman. He drew the Gladius Incandor in his right hand. The Hand of Dominion sparked into life on his left, an oily field of blue light encasing its massive robotic fingers and underslung boltguns. Raising the flat of his blade to the muzzle of his helm, he saluted his brother. He thumbed a switch, and a sheath of energy covered the blade to match that of his fist.
'You are staying?' said Fulgrim. 'No dramatic teleportation? No strategic withdrawal? You actually want to fight someone you cannot hope to beat? Well, well, well, you are beginning to surprise me, Roboute. I never thought you had it in you. Perhaps you are not so boring after all.'
'Honour demands I slay you.'
Fulgrim stretched out his arms. Blades rose from nothing, sprouting from his clenched fists, black vapours boiling off their metal as they were forced into being. The swords were mismatched in form, and every one a different pastel hue. Bright poisons dripped from their edges.
'Honour will get you killed.' Fulgrim raised his own blades to his face, the edges ringing off one another. There was no mockery to the salute. 'So it is, brother. We come to the end. With you dead, our other brothers will follow, one by one. The Imperium cannot last without your guidance. It is you who holds the whole crumbling thing together.' He smiled sadly. 'Dull as you are, you were among the best of us. I almost feel sorry to kill you, if only because you will not see the triumph of the true powers of the universe, and know the liberation they bring.'
Swift as a striking viper, Fulgrim attacked, all four blades driving down at his brother primarch so quickly that they did not seem to pass through the intervening air. Guilliman caught them on the edge of the Gladius Incandor. Its field generator smoked at the effort of halting them. The resulting eruption of energy threw both primarchs backwards.
Fulgrim attacked again. Guilliman cried out as one blade found its way past his parries and left a smoking groove in the ceramite around his left arm. He would not win this fight.
'Thiel, Andros,' voxed Guilliman. 'Now.'
There was a sound like a sigh that turned into a rumbling groan. The Heliopolis boomed with conflicting resonances, and the Phoenix Gate exploded inwards, showering the room with gobbets of molten bronze. The Ultramarines of the First and Second companies came charging in, bolters firing at the daemon primarch battling their lord.
'At last! Your true colours,' said Fulgrim. 'For all your talk of honour, you will not face me alone.'