Treachery at Port Maw - The Ravens: At the same hour that the first footfalls of the Titans were sounding at Hive Illum on Manachea, at Port Maw open void battle had now erupted between those ships that had turned fully Traitor and those who had remained Loyal, while all across the artificial planetoid station below them, civil war was being waged with bloody conviction. The Traitors' plan had proved only partly effective in conquering the Loyalist fleet from within or forcing its surrender, and now the malign influence radiating from the Mechanicum Panopticon had been ended, the Loyalists were rapidly gaining strength.After the bloody and chaotic skirmish, those warships that remained mobile had broken away and parted into two battle lines, forming thousand-kilometre-long crescent formations mirroring each other in orbit round the Maw, each now staying their range and keeping the bulk of the artificial planetoid between them and the enemy as they manoeuvred to form up. Around them hundreds of wrecks and stricken voidships cascaded, reeling with damage or drifting paralysed as bloody struggles raged on within them for control. Neither force had such overwhelming superiority yet that a direct attack on the other would guarantee victory without severe losses, but both knew that to attempt to flee -- to turn away from the enemy and run -- would be to secede the entire strategically vital star system and all it contained to the enemy. The fate of Port Maw and its vast armada hovered on a knife's edge.As the two battle lines fell into a deadlock, from the darkness of the outer system came a new and unexpected threat. The dark fleet answered no hails, broadcast no identification cyphers, but came hurtling on at near relativistic speeds like a dagger hurled at the heart of Port Maw. In the strategium of the gargantuan Loyalist flagship, the Triumph of Reason, Grand Admiral LaBray awaited impatiently as his sensorium officers strained their Auspexes to get a firm report on the incoming fleet. Some form of masking technology was being employed that scattered and defused the scanning beams, making a definite fix on the vessels impossible to attain. LaBray likely knew, as many of his rank did, of the rumours of such arcane devices being employed by the secretive Raven Guard Legion -- a Space Marine Legion which remained Loyal, but was reported destroyed at Istvaan V.Could this be a Raven Guard splinter fleet, the survivors of that cataclysmic battle? If so why did they not answer, why did they not identify themselves? These questions could not be readily answered. But however effectively their true nature was shrouded from LaBray's Auspexes, while operating at such intense acceleration, their engines burning bright with plasma thrust, they could not hide their number; there were twenty vessels by their drive flares, at least half of which were capital class by his savants' estimations, meaning LaBray's own fleet outnumbered the interlopers by a margin of four for one. It was a force which alone he could overwhelm, but if it joined with the mass of the enemy now matching him in orbit on the other side of Port Maw, would likely tip the balance in the Traitors' favour. Without hesitation LaBray gave the order, and the vast crescent of his armada turned and began to arc toward the stranger-fleet on an intercept vector, their own engines burning bright.The distance closed, thousands of kilometres flashing by in mere seconds, and behind the Loyalists the Traitor fleet followed suit, but it would be LaBray's ships that would meet the newcomers first, that was now inevitable. The solar minutes ticked by until it was reported that the incoming ships were now close enough to be within visual range of the flagship's occularis, and LaBray immediately ordered the image up before him. It was only then that he realised the depth of his mistake. The vanguard of the incoming ships were indeed Legiones Astartes Battle Barges of the Raven Guard, or at least had been; two modified Dagon-class Grand Cruisers bearing the sable heraldry of the Primarch Corax's Legion now torn and burned in the fires of battle, but what came after them was not of the Raven Guard. The monster rose up behind the Battle Barges, making them seem as mere frigates in comparison to its nightmare magnitude. It was a ship no Imperial captain could ever have failed to recognise at first glance, it was a war machine few vessels could ever hope to match, but what its presence portended was darker still. It was the Vengeful Spirit; it was the flagship of Horus.