Hive Fleet Kraken - Damocles Gulf Campaign: In 991.M41 an outer wing of Hive Fleet Kraken approached the Damocles Gulf and destroyed a T'au exploration vessel in a region the xenos termed the "Coreward Marches." The vessel managed to deploy a Courier Drone before self-destructing, which made it to the T'au Empire and alerted it to the threat approximately eighteen solar months later.In response the T'au aborted a nearly successful invasion of the strategically important Imperial planet Quadravidia, offering an alliance against the oncoming Tyranids to the local Imperial forces under the command of Lord General Zyvan. The Imperium accepted the truce and provided astropaths to serve aboard T'au vessels to coordinate the wider defence of the Damocles Gulf region.While the T'au moved to reinforce the border planet Dr'th'nyr, close to the main hive fleet's course, an Imperial task force comprising approximately 100 warships under Admiral Boume and several Astra Militarum regiments under Zyvan, including at least one from the  Death Korps of Krieg, gathered at the strategic Forge World Fecundia located further off the Tyranids' course, joining local Skitarii and a small garrison of Adeptus Astartes from the Reclaimers Chapter. The rest of Battlefleet Damocles was to intercept the bulk of the fleet at Quadravidia.After defeating the first wave of Tyranids the forces at Fecundia realised that the Hive Mind wished to destroy a fragment of a Hive Ship from a rival brood that had been recovered by the Adeptus Mechanicus from Nusquam Fundimentibus around 941.M41. In the process they learned that Magos Kildhar, a senior Mechanicus official, had been implanted by a Genestealer aboard the space hulk Spawn of Damnation at some point after 929.M41 and now served its Broodmind; Commissar Ciaphas Cain was forced to shoot her dead with his laspistol.While the planetary government began genetic screenings for additional Genestealer implantees, Fecundia came under a renewed attack by the hive fleet, still targeting the bio-ship fragment that lay under the Mechanicus headquarters. Outnumbered and outgunned, the Imperials were forced to release a cache of frozen Tyranid bioforms recovered with the bio-ship fragment as a diversion.Realising from their behaviour that the two competing Hive Minds were partially neutralizing each other, the Imperials hit on using a psyker to amplify the bioship's signal. Astropath Clementine Drey gave her life for the operation, which destabilised the hive fleet's command-and-control and gave the upper hand to the Navis Imperialis, which destroyed multiple escort bio-ships and a Hive Ship at the heart of the fleet, forcing the xenos into full retreat.In the wake of the invasion the Astra Militarum established a permanent garrison on Fecundia to supplement the native Skitarii, and by 058.M42 in the Era Indomitus, with no confirmed Tyranid sightings for three solar decades, the planet had been officially declared cleansed.Despite the key Imperial victory at Fecundia, war between Hive Fleet Kraken and the Imperial-T'au alliance continued to rage in the Eastern Fringe for some time to come. The border world of Semplaxia, which had changed hands between Humans and xenos seven times in the past two standard centuries, fell early, and at least two other Forge Worlds and several Imperial Hive Worlds supplying the regional Astra Militarum and Adeptus Astartes were lost to the Great Devourer. This in turn drove the Adeptus Mechanicus to accelerate the process of bringing new Forge Worlds such as Eucopia to full war production status.