Oranthian Crusade

The Oranthian Crusade was a campaign that took place upon the Chapter homeworld of the Emperor's Trident Chapter during the first decade of M41. Following several earthquakes and subsequent tsunamis and rogue waves which destroyed large amounts of the planet's population, and ancient vessel of great antiquity rose from the depths of the deepest oceans. It was the original colony vessel that had brought humanity to the world of Oranthi during the bygone Dark Age of Technology. The Emperor's Trident and local Adeptus Mechanicus immediately launched a salvation mission in order to claim the ancient vessels lost technology, but were soon set upon by the mysterious undead life form known as the 'Drowned Men'. In the end, this nefarious threat was wiped out and the Adeptus Mechanicus were able to recover many valuable STCs and lost technology, greatly rewarding the Space Marine Chapter for their assistance.

History
In the beginning of the new millennia, large earthquakes started to plague the Emperor's Trident Chapter homeworld of Oranthi, causing islands to rip apart and wiping many ships that were sailing or trying to escape the destruction of these islands. The earthquakes were so devastating, even under the waves, that many aquatic animals crawled up onto the beaches, or if they couldn't walk on land then they resided near the islands in the shallow waters, preying on ships, while the creatures that could walk on land attacked human settlements. This natural disaster scared many Murder Crabs which caused them to frenzy and basically invade many of the islands, claiming the lives of many Oranthians.

During this tumultuous time, the strangest event of all occurred when an ancient ship resurfaced. This vessel was extremely huge, with it being bigger than any ship the Emperor's Trident had in their chapter. The barely intact ship turned out to be the ancient colony ship that brought their ancestors to Oranthi thousands of years earlier. When the Emperor's Trident heard of the ancient colony ship resurfacing, the Scout Company was ordered to survey the ship alongside an entire Trident company near their homeworld. When the chapter alerted the closest forge-world, Chapter Master Tercal Norith agreed to allow the Adeptus Mechanicus to survey the derelict vessel for any lost technology. The ruling Archmagos eagerly sent a demi-legio of Skitarii alongside other mechanicus forces in order to assist the Chapter.

Soon both Astartes and Adeptus Mechanicus forces landed on various landing sections of the ship. But as soon as the Imperial forces opened the hangar doors of ancient vessel, they were immediately beset upon by aquatic creates that made their home in the ship, which included such deadly creatures as Nova Krakens, Murder Crabs, Squids and Sea Wolves. But this was nothing compared to the seemingly endless legions of Drowned that stormed the Adeptus Mechanicus and Astartes forces. Their numbers were so vast that the Skitarii ordered armoured reinforcements and their Astartes allies requested further reinforcements as the numbered of drowned soon threatened their homeworld.

With most of the chapter already engaged abroad in several brutal and bloody engagements in other parts of the galaxy, there was only one company able to answer the call. Bolstered by three whole Trident companies, they Astartes assaulting the ship alongside their Skitarii allies. They sought priceless ancient technology that was worth the losses. When the number of Drowned colonists (who died in ages past) started to dwindle down, the Imperial forces proceeded to make their way inside the ancient ship. Many parts of the archaic vessel were heavily damaged from both water and neglect.

Once inside, the Imperial forces quickly realised they faced an even bigger problem in the form of a few Drowner dwellings as well as animal nests - both which were equally hostile. After spending weeks of purging the Drowned hives as well as animal nests, the Skitarii sent down tech-priests, servitors, slaves, and enginseers to seek out and ship any salvageable technology. Meanwhile, the Astartes stubbornly overlooked the entire operation, as this was their ancestral ship and their planet. However, many of the natives that died from the resultant earthquake, drowned at sea, or by native wildlife, turned into Drowned men and instinctively traveled to the ship en masse.

While the Skitarii forces kept the initial attack at bay, the bulk of Drowned Men started to storm the beach. Despite their grotesque appearance, remarkably, a large number of Drowned Men still retained knowledge on how to utilise their equipment formerly used when they were alive, with many of these undead creatures able to fire their weapons. A few were even able to still utilise their vehicles. The Astartes forces assisted in defending the ship with the help of several of their Chapter's predator tanks, sinking the Drowned Men's ships and focusing fire on large clumps of the undead forces. After months of defending the ship, the high number of casualties taken by the Drowned Men finally began to take their inevitable toll, and eventually, they were finally wiped out for all time. In the end, the Adeptus Mechanicus forces found valuable STC drives and some salvageable archaeotech, which was miraculously not completely damaged. In gratitude, the Adeptus Mechanicus greatly rewarded the Chapter with additional wargear and rare equipment.