Sky Sentinels - Notable Campaigns: Pandemonium of Sondheim V (997.M41) - The Agri-world of Sondheim V was overwhelmed by the Tyranids of Hive Fleet Leviathan just as the Daemon Prince M'kar the Reborn transformed the world into his own private Chaotic Pandemonium. The Sky Sentinels Chapter of Space Marines was the first to respond, but judged the world irretrievable and made preparations to begin an Exterminatus. These preparations were delayed following the arrival of a Grey Knights strike force under the command of Grand Master Vardan Kai. Whilst Kai concured with the Sky Sentinels' assessment that the planet couldn't be recovered for the Emperor, he ordered a stay of the Exterminatus whilst he and his Battle-Brothers attempted to capture the Book of Pandegaras -- the cursed tome of Chaotic sorcery that M'kar had used to transform the planet below into his own private hell-world. The Sky Sentinels reluctantly decided to give Kai twelve hours in which to accomplish his mission, and the Grey Knights took to their Stormravens and deployed to the planet below. Upon landing, Kai hastily revised his time limit to a mere six hours -- a nightmarish fusion of daemonic and Tyranid infestations had transformed Sondheim V into a Death World. Fortunately, running battles between the Tyranids and M'kar's daemonic thralls allowed the Grey Knights to slip through the mutated landscape unimpeded, if not unnoticed. Unfortunately, when Kai's forces reached the temple in which the Book of Pandegaras lay, they discovered that the building had been almost completely surrounded and interpenetrated by Tyranid spore chimneys. Unperturbed, the Grey Knights hacked their way through the xenos biomatter but drew the attention of the Hive Mind. Within seconds, Kai's forces came under attack by waves of Hormagaunts and Gargoyles. By the time Kai finally carved a path into the lower levels of the temple, larger creatures started to arrive, and the Grey Knights began to suffer heavy casualties. Yet as Kai finally reached the Book of Pandegaras, unexpected aid arrived. Just as the earlier strike on the Tyranid biostructures had alerted the Hive Mind, so did the violation of the Chaotic artefact by the touch of the Emperor's servants now bring forth the wrath of M'kar's daemons. The twisted ruins of the temple erupted into a three-way battle. The Tyranids bore the brunt of the daemons' attack. With the Grey Knights surrounded by Tyranid bioforms, the daemons could reach them only by carving a path through the Great Devourer's minions. Bloodletters swarmed over a Tyrannofex, only to be cut down by volleys of Storm Bolter fire. Carnifexes smashed through knots of Grey Knight Terminators only to be immolated between the sanctified flames of Purifiers and the unholy Warpfires cast by the Flamers of Tzeentch. Amid the chaos, Kai was forced to abandon any pretence of a controlled retreat and he made contact with the Sky Sentinels' fleet, who began an orbital bombardment of the temple site. Protected by their Power Armour, the Grey Knights weathered the storm of barrage bombs that exploded amongst the ruins while their Tyranid and daemonic foes were less fortunate. When the bombardment ceased, Kai and the surviving Grey Knights evacuated the doomed world before daemon and Tyranid reinforcements could arrive. Less than an hour later, Kai's strike force began the journey home to Titan to contain the Book of Pandegaras in the Chapter's vaults, whilst the Sky Sentinels began the Exterminatus that destroyed Sondheim V and all of the horrors on its surface. In the wake of the Exterminatus, the Sky Sentinels surrendered themselves for the standard mindwipe to the Inquisition so that all memory of the worst horrors of Chaos would be wiped away.13th Black Crusade (999.M41) - During the 13th Black Crusade, soon after the fall of Cadia and the birth of the Great Rift, the Sky Sentinels' homeworld of Pranagar was invaded by the Forces of Chaos led by the Daemon Primarch Magnus the Red and his Thousand Sons Traitor Legion. All Sky Sentinels returned from where they had been serving across the galaxy to defend their homeworld, but it proved to be too little in the wake of such a massive Chaos invasion and the entire Chapter was destroyed. The forces of Magnus then overran Pranagar and claimed it as part of the Daemon Primarch's expanding domain in realspace.