Battle of Calth - From Bad to Worse: Shortly after the Campanile exploded in orbit, the datashock from the resulting scrapcode onslaught killed Mechanicus Server Uhl Kehal Hesst through a vicious neural biofeedback mechanism commonly known as datashock amongst Tech-adepts (more officially termed hypertraumatic inload syndrome). Weapons fire hit the orbital watchtower at Kalkas Fortalice a nanosecond after the shock wave of data was unleashed by the Word Bearers' coordinated assault. The data noosphere of Calth immediately collapsed. The tower's manifold field stuttered out. Hesst felt and absorbed the shared neural agony of several thousand deaths: his Mechanicus brethren aboard the primary shipyard, aboard the docked vessels, and in the tower around him as they died and their agony was transmitted from their dying neural cortexes through their augmetic systems into the noosphere they had been connected to at the time of their deaths. With the death of Hesst and his fellow Mechanicus personnel, all of the networked Cogitator systems of Calth went off-line. Calth’s planetary defence grid ceased to function, leaving the entire Ultramarines fleet completely unable to mount any defence against the Traitor warships' attack.Fortunately Hesst's second-in-command, Meer Edv Tawren, a Magos of Analyticae, was not killed by the infected scrapcode. It was basic Mechanicus data server protocol that saved her life, for it required a server's second-in-command to unplug his or her neural interface from the data noosphere when a significant scrapcode assault was under way so that there was no danger of the deputy also being compromised by the infected data. This operational safety measure saved Tawren from far more than just a scrapcode infection. When Hesst died in her arms, he charged his deputy to connect herself to a working server to attempt the reconstruction of the noosphere and bring the orbital defences back online. Magos Tawren would play a pivotal role in the coming conflict.Debris began to fall from the clouds, trailing fire like meteorites, raining across the fertile river valley of Kalkas Fortalice. Some of the heavier pieces of falling debris struck buildings, exploding them like artillery strikes. The hail of debris had only begun as larger objects begin to fall – parts of ships, orbitals and the docking yards. Magos Tawren saw the unfolding disaster before her sensors did. She saw the Grand Cruiser Antrodamicus falling backwards into the atmosphere, stern first, towards Kalkas Fortalice.Meanwhile, unbeknownst to the Ultramarines, Kor Phaeron materialised aboard the Samothrace through arcane means. The Word Bearers used the Samothrace to slip past the Ultramarines into the gates of the Zetsun Verid Fleet Yard. Behind it, Calth's main orbital shipyard continued to burn. No one challenged the Samothrace, since it was an Ultramarines vessel running for cover and Vox and noosphere communications amongst all of the orbital installations was completely dead. No one aboard the orbital habitats within the Zetsun Verid Yard questioned the fact that their yard's infrastructure had not been targetted by the Traitors even though all the fleet yards around it had been obliterated. The Samothrace pulled into the ship docks between two Escort vessels sheltered in the yard space. The Ultramarines put up intense resistance, but eventually the Zetsun Verid Yard also fell to the Word Bearers. The Traitors' only setback was that the destruction of Calth's planetary data noosphere was so complete, it took the Word Bearers' Dark Mechanicus allies longer than expected to reconstruct a workable planetary data network. The reason the Traitors had spared the Zetsun Verid Fleet Yard was that it contained an advanced data-engine hub capable of substituting itself, in the event of an emergency, for the primary data hub of the Calthian noosphere located at the Calth Veridian Anchor.The Dark Mechanicum Tech-adepts brought the Zetsun Verid Yard systems online and its data-engine resumed normal operations. Sensing that the planetary weapons grid was inactive, and that the inactivity had been caused by the inexplicable loss of the data-engine hub located aboard the Calth Veridian Anchor, the Zetsun Verid data-engine automatically obeyed its standard protocols and assumed control over the planetary data network and the planetary defence system, bringing the Calthian weapons grid back online.The Word Bearers were now in control of the effective firepower of a major Imperial battlefleet. The firepower of this defence system was distributed across the surface of Calth and its orbit. Kor Phaeron had his Dark Mechanicus Magi bring online the 962 orbital defence platforms as well as several ground-based stations, including the weapon pits located at Calth's poles. The Calthian planetary weapons grid was capable of keeping at bay an entire expeditionary fleet or primary battlegroup and it soon began to fire on the orders of the Word Bearers, assaulting all of the neighbouring planets and spaceborne Imperial facilities in the Veridian System.The Ultramarines fleet had scattered, having been reduced to about a fifth of its original strength by the Word Bearers' surprise attack. Those vessels that remained either fled to the far side of the Veridian star to avoid an attack by the Word Bearers' fleet and the inexorable fire of Calth's defence grid or, like Primarch Guilliman’s flagship, the Macragge’s Honour, lay helpless and drifting in Calth's high orbital anchor zone. There were virtually no warships left for the Ultramarines to fight the Traitors in the void. It was simply a matter of time before the Word Bearers picked off the remaining warships of the XIIIth Legion's fleet. Next, the Calthian defence grid destroyed the local Forge World of Verida Forge, a small moon with offensive capabilities. It then assaulted a Star Fort near the Veridian System's Mandeville Point and several more Loyalist capital ships, vaporising them all.The Ultramarines' 1st Chapter Commander, Marius Gage, was the first amongst the Loyalists to recognise the attack pattern of the Word Bearers' fleet. Many of the surviving Ultramarines starships were the largest and most powerful capital ships in the XIIIth Legion's fleet. With the Traitors firmly in control of Calth's planetary weapons grid the Word Bearers could easily pick off the most serious threats at their leisure. Those ships that had been spared were all helpless and drifting, like the Macragge’s Honour. The moment they shook off the effects of the scrapcode assault, began to start up their drives, or raised their Void Shields, Calth's weapons grid would target and destroy them. The Word Bearers intended to take as many of the XIIIth Legion's capital ships intact as they could to bolster their own fleet and enhance their overall striking power in the longer conflict to come against the Loyalists.