Hive Fleet Behemoth - A Voice in the Dark: With Thandros lost, Kryptman's quest became critical. The next systems in Hive Fleet Behemoth's path belonged to the Realm of Ultramar, and unless it was forewarned, the Imperium might lose its best chance to halt the progress of the Tyranid onslaught.With haste, Kryptman and his agents salvaged what remained of Thandros' telepathica matrix, and through a herculean effort, his astropath finally managed to pierce the shadow in the Warp to contact the unsuspecting Imperium.The astropath, nose and ears streaming blood from the effort, broadcast Kryptman's warning. A single voice spoke back from the darkness, and it came from Macragge, the heart of Ultramar and the homeworld of the Ultramarines Chapter of Space Marines.By the grace of the Emperor, Inquisitor Kryptman arrived at Ultramar ahead of Hive Fleet Behemoth, and met with Marneus Calgar, Chapter Master of the Ultramarines, beneath the portico of his white marble palace. Calgar stood as a giant before the Inquisitor, his stature grand even among the superhuman warriors of the Space Marines.Calgar listened intently to the smaller man's words, but Kryptman's terrible discoveries did not disturb his noble demeanour. A true heir of the Primarch Roboute Guilliman's genius, and one of the most accomplished military leaders in the Imperium, nothing escaped Calgar's notice, not one detail about the foe that could be turned into an advantage. Hive Fleet Behemoth was fast approaching, and the Ultramarines Chapter prepared for the greatest battle in its history.The Ultramarines were quick to react, and Marneus Calgar deployed the Ultramarine fleet to stop the Tyranid hive fleet at the garden world of Prandium -- the Jewel of Ultramar, with gardens and forests of such amazing beauty and genetic craftsmanship that it was considered one of the Wonders of the Imperium -- a world that the Ultramarines were duty-bound to protect.It was a slaughter. The tactics and strategies decreed by the Codex Astartes, a tome of knowledge created by the Ultramarines' Primarch Roboute Guilliman to govern all aspects of Imperial warfare, did not succeed against the Tyranids.The harrying strategies of the Ultramarines could not inflict enough damage against the Tyranids -- and the close-range passes of Thunderhawks and other Imperial aircraft and vehicles for optimal firepower favoured the Tyranids' mode of attack even more, since their spore cysts and clawed tentacles would burst or tear open many of the ships that went in on the attack.The Ultramarine fleet had to sacrifice Prandium to consumption by the hive fleet. Ill-fated Calth fell next, ravaged by a smaller force of Tyranids seeded by the hive fleet's bio-ships.For a solar week, Marneus Calgar went without food or water while meditating on the matter. When he came out of his trance-like state, he told the Ultramarines that they had been guilty of the sin of pride.The Codex Astartes was written for the Space Marines, the Space Marines were not created for the Codex Astartes. They would have to adapt and develop new strategies and tactics, even weapons, if they were to be successful against the Tyranid menace. Hit-and-run raids were abandoned in place of concentrated defences and static firepower.This meant that the Ultramarines had to choose a place to defend, and they chose their fortress-monastery, the Fortress of Hera, on their homeworld of Macragge, the very heart of Ultramar.