Another portion of this section of the ceiling showed Roboute Guilliman on bended knee, swearing his bond of brotherhood with the warrior people of Tarsis Ultra. To see such a display of humility from one so mighty as their primarch was a sharp reminder to Uriel of everything the Ultramarines fought to protect.

Everywhere around the chamber there were new wonders and fresh visions of incredible beauty, but Uriel forced himself to tear his gaze away from the fantastical mosaic. Pasanius and Learchus stood by his side, similarly overwhelmed by this work of genius.

'It's…' began Learchus, searching for words to do this masterpiece justice.

Uriel nodded. 'I know. I have read of the Tarsis fresco, but had never believed it could be as magnificent as this.'

Footsteps echoed through the chamber and the spell was broken. The mosaic was just a wall and the images upon it nothing more than glass shards. Uriel turned as Fabricator Montante, changed into more practical plain grey robes, led the council of war into the room. The senior officers of the regiments, each with an entourage of scribes, flunkies and adjutants trailing a respectful distance behind them, followed Montante towards the centre of the chamber.

This portion of the room was sunken into the floor, where a number of marble benches and a long, low table were set, bearing clay jugs of mulled wine and wooden bowls of fresh fruit. Uriel stepped down into this sunken area and took a seat, examining his fellow commanders as they arrived.

Montante was thin and seemed pathetically eager to please. His features were delicate and ascetic, though intense. He did not look like a warrior and Uriel wondered how he had achieved his position of authority here. Was the rule of Tarsis Ultra hereditary, democratic or did it still follow the primarch's meritocratic ideals? Was Montante capable of leading his people in time of war or would he need to be replaced? Was that decision even his to make? Montante busied himself pouring wine for everyone and Uriel politely shook his head when offered a goblet.

Stagler had the look of a warrior. Uriel had heard tales of the Krieg Death Korp and how their colonels requested the most dangerous warzones for their regiments to fight in, the most lethal enemies to face. If Stagler conformed to type, then he had chosen a prime assignment for his soldiers. He sat ramrod straight and appeared deeply irritated with Montante, also declining the wine.

Rabelaq had the look of a man to whom soldiering was a way of life, though his ample gut told Uriel that the rigours of the battlefield were but a distant memory to the colonel of the Logres regiment. He enthusiastically accepted a goblet of sweet wine and sipped appreciatively.

Chaplain Astador accepted some wine and raised it in a toast.

'May this brotherhood be united in its cause,' he said.

'Hear, hear,' agreed Rabelaq draining his goblet and pouring himself another, but Astador was not finished with his salutation. 'And should any of you fall, I shall ensure that your skulls are granted a place of honour in our Gallery of Bone.'

An awkward silence fell, until Montante said, 'Thank you, Chaplain Astador. That is most gratifying to know.'

Uriel shared a glance with his sergeants as the last members of their group entered the chamber. Lord Inquisitor Kryptman limped towards their gathering, followed by a white robed acolyte wearing a cog-toothed medallion of bronze around his neck. Unusually for a member of the Adeptus Mechanicus, his hairless features were largely organic, save for the bionic attachment that covered his right eye. A number of hinged lenses of varying size protruded from the side of his skull, each capable of sliding forward to drop before his glowing red bionic eye.

Kryptman stepped down to the benches with some difficulty and as his Adeptus Mechanicus companion joined him, Uriel was shocked to see that he moved on metallic caliper-like legs that protruded from the bottom of his robes. As the acolyte descended the steps to take his place behind Kryptman, his robe parted and instead of legs and torso, Uriel caught a glimpse of a thick, flexing brass tube connecting his chest to his artificial legs.

The lord inquisitor eased himself down onto a bench, irritably shaking his head as Montante offered him some wine. He cast his gimlet gaze around the assembled company and grunted to himself, though Uriel could not tell whether it was in satisfaction or resignation.

'This is a grand adventure,' said Montante, finally sitting down. 'Most of my time involves accounts, ledgers and all manner of boring logistical work for the factories. I don't think I've ever entertained such an esteemed group in the palace.'

Kryptman gave Montante a withering stare. 'Fabricator Marshal, this is no adventure we are upon. It is a matter of the gravest urgency and most fearful nature. A tendril of hive fleet Leviathan approaches your world and you think it will be an adventure?'

'Well, no, not an adventure in the traditional sense, you understand,' said Montante hurriedly, 'but it's certainly exciting, isn't it? I mean, it's not every day we get to fight a war, and I for one am looking forward immensely to giving these beasts a bloody nose.'

'Then you are a fool, sir, and would do well to leave the defence of your world to those who understand the grave danger of a tyranid hive fleet.'

'I object to your tone of voice, sir,' protested Montante. 'I am the planetary governor, after all.'

'For the time being,' threatened Kryptman. 'Now, if we may continue? Let us be clear on one thing: I have seen, first hand, what it means to fight these aliens and it will not be an adventure, there will be no glory and little honour in their destruction. '

'I declared their species Xenos Horrificus two hundred and fifty years ago and since that day I have studied, hunted and killed them, yet still know but the tiniest fraction of their xenology.'

The inquisitor indicated the Mechanicus adept behind him.

'To fight the tyranid you must first know it,' he said. 'This is Genetor Vianco Locard of the Magos Biologis, and he knows more about these xeno abominations than any man alive. He will be of great help to us. Magos, if you please?'

Locard moved to stand before them and a brass rimmed monocle whirred into place over his red eye. As he laced his hands before him, in the manner of an academic, Uriel saw they were a smooth black metal.

Without preamble, he launched into his discourse. 'The tyranids are a bio-eugenic race of xenomorphs from beyond the Emperor's light, first discovered in the 745th year of this current millennium by Magos Varnak of the Adeptus Mechanicus outpost of Tyran Primus in Ultima Segmentum, some 60,000 light years from holy Mars.'

'Bio-eugenic? What does that mean?' interrupted Colonel Stagler.

'It means that the tyranids are able to assimilate entire worlds and races, break them down into their constituent genetic building blocks and incorporate said constituents into their own physiology,' explained Locard.

Seeing Stagler's, and everyone else's confusion, Kryptman said, 'Thank you, Magos Locard, but perhaps I should explain and keep things at a level everyone here can understand.'

Uriel bristled at such a casual insult to his intelligence, and could see others frowning too, but Inquisitor Kryptman's notoriety preceded him and there were no objections as he continued: 'The tyranids are a monstrous nomadic race of predators from beyond our galaxy who ply the depths of space in vast hive fleets. Like locusts, they consume everything in their path, and as each foe is defeated it is assimilated, each future generation of tyranids becoming better adapted to hunt their prey. When they attack, they attack in their millions, swarming across a world like a plague and just as destructively. Everything, every blade of grass, every indigenous creature is engulfed by the teeming hordes. Millions of years of evolution is destroyed and uncounted millennia of hard-won development and growth are annihilated by the tyranids' insatiable hunger. The world's oceans are drunk dry, its skies boiled away and digested until nothing remains, save a barren rock, stripped bare of every living thing.'