Hive Fleet Kraken - Ichar IV Rebellion: But before the true threat revealed itself, the Imperium had first faced uprisings on its Eastern Fringe that served as the prelude to the main Tyranid threat. One such rebellion occurred on a Hive World named Ichar IV. Ichar IV was vital to the operation of the Eastern Fringe as its huge manufactoria formed the centre and lynch pin of one of the few densely populated Imperial sectors in the widespread Ultima Segmentum.The entire planet had been seized from the control of the Imperium by a religious fundamentalist group named the Brotherhood. Years before, the Brotherhood had captured the hearts and minds of the population of the planet by preaching the return of the Emperor in physical form and promising better times to come.This is the sort of promise that was sought by the workers of the Icharran manufactoria because they lived lives with no power, hope of betterment or freedom. The Brotherhood quickly set up missions and chapels throughout the poor regions of the planet.The Ecclesiarchy closely monitored the Brotherhood for any signs of corruption or heresy, but none could be found. Eventually, permission was sought and granted for the construction of a Brotherhood cathedral in Lomas, the biggest city on Ichar IV. Shortly after the completion of the Brotherhood's cathedral the trouble began; the Brotherhood refused to pay its tithes to the planetary governor and would not allow its members to be inducted into Ichar IV's Planetary Defence Force.Brotherhood preachers whipped the Icharran population into a frenzy, prophesying that the Emperor would return in the flesh soon. Brotherhood militias began to roam the streets, punishing anyone they deemed to be "unbelievers" rather than actual criminals.Events accelerated when rioting broke out during a mass demonstration outside of the great cathedral in Lomas. Arbitrators of the Adeptus Arbites moved in with Power Mauls and Suppression Shields to put down the rioters forcefully, but were fired upon from the cathedral by Brotherhood militia. The Arbitrators returned fire and killed several of the Brotherhood's militia members.This only enraged the mob further and they surged forwards several times, eventually forcing the Arbitrators to fall back, especially as another, larger mob had just arrived to support them. Rioting then spread across the planet and most of the forces of the Arbites were forced back. When the Planetary Defence Force was called in to restore order, most members of the force rebelled and joined the ranks of the Brotherhood.Eventually, news of the assassination of the Planetary Governor reached the public and vicious fighting broke out in all of the hive cities of the planet. Within solar hours, tanks decorated with the revolutionary banners of the Brotherhood were seen driving down roads in cities, pushing the Arbites back.With the dawn, news of the assassination of the Imperial governor and most of his ministers had spread over the entire planet, and the Brotherhood quickly seized control of several broadcasting stations, announcing the establishment of their new theocratic state in the name of the returning God-Emperor.The Arbites still held control of the majority of the Icharran countryside and the Arbites precinct-fortress that guarded the centre of Lomas. Most of the cities had been captured by the Brotherhood, denying the Arbites vital resources. Inquisitor Agmar of the Ordo Xenos arrived twenty-seven solar days after the rebellion began, on the same day that the Arbites fortress in Lomas was overrun by Brotherhood forces. Most of the Judges in the fortress escaped, moving to take control of the four main power stations of the city.Inquisitor Agmar saw this as much more of an organised rebellion than a sporadic outburst of popular religious feeling. He called for the support of the Ultramarines Chapter of Astartes to help the forces of the Imperium retake the planet. While the remaining Imperial forces waited for the arrival of the Ultramarines, they bombarded the rebel cities and pushed back vicious assaults by Brotherhood militia battalions. Repeated attempts to reach the power stations of Lomas failed and, six days after Agmar arrived, the Arbites detonated several Melta Bombs, completely destroying the generators.Now the war transformed into a long, grinding campaign of urban combat with casualties spiraling upwards daily. Every doorway could possess a booby trap and there were Brotherhood snipers in place all over the Renegade-held cities. Entire Astra Militarum patrols that remained loyal to the Imperium disappeared without trace in the chaotic maelstrom. The rebellion promised to be a long one as the Brotherhood held the armouries of the Imperial Guard regiments assigned to the planet and had the support of the majority of the Icharran population to draw on to become soldiers in its militia.Inquisitor Agmar led several small forces of Imperial Guardsmen and Arbitrators into Lomas to uncover the true nature of the Brotherhood. He was slowly piecing together the story when, in a chance raid, he slew a Neophyte Hybrid of the Brotherhood and saw what manner of xenos creature was actually leading the revolt -- foul Tyranid Genestealers! The Brotherhood was, in fact, a Genestealer Cult! Agmar sent an astropathic message confirming his fears of another Tyranid invasion to the Inquisition and awaited the arrival of the Ultramarines.