Kappa Mortis Incident
The Kappa Mortis Incident was one of the last skirmishes of the Damocles Gulf Crusade fought between the Imperium and the Tau Empire. Space Marines of the Ultramarines Chapter, responding to the distress signal of a downed Aquila Lander, were successful in repulsing a Tau ambush and recovering an example of Tau technology for later examination. However, Captain Severus Agemman was wounded in the short but bloody battle.
As the Imperial attack into the Tau Empire slowly ground to a halt, the decision was made to suspend the invasion and pull back forces to face the greater threat posed by Hive Fleet Behemoth. On the planet of Kappa Mortis the Imperials were largely successful in their evacuation; however, Tau efforts to reclaim the world were quicker than expected. One of the last vessels to leave, an Aquila Lander bearing captured Tau technology, was shot down and crash-landed at the abandoned Outpost Theta Seven. Although he did not survive, the pilot was able to activate the craft's emergency beacon.
Captain Severus Agemman, then-commanding the Ultramarines' Second Company, received the distress signal while en route back to Ultramar to combat Behemoth. He recognized the value this captured techno-sorcery would have in further understanding and defeating the Tau in the future; however he could waste little time or manpower for this mission. While the rest of his force continued on to Ultramar, Captain Agemman personally led a small detachment to return to Kappa Mortis and recover the items.
Meanwhile, newly-promoted Shas'el Nightwind was ordered to take his Hunter Cadre and either recover or destroy the stolen items at any cost. Commander Nightwind was given Special issue equipment, a sophisticated sensor array developed by the Earth Caste's scientists to better locate the items, which was built into the head of his Crisis Battlesuit. However, the Tau could not pinpoint the crashed Aquila's exact location, forcing Nightwind to spread his forces out across the region in order to locate the crash site.
At Outpost Theta Seven, Agemman had his Tactical Squads spread out to search the area for the crash site, keeping the rest of his force in reserve while the Scouts sought higher ground to watch out for any enemy movements. Unfortunately, the crash site was soon located by Nightwind's Stealthsuit team, which immediately engaged the Space Marines while the rest of the Cadre raced to the scene. In the resulting clash, both sides suffered casualties, with Captain Agemman wounded in the fight as he directed the search. Despite this, the Space Marines were victorious in driving off the Tau and succeeded in recovering the helmet of an XV15 Stealthsuit.
The XV15 helmet recovered from Kappa Mortis found its way to the labs of the Ordo Xenos, where agents of the Inquisition were able to study first-hand an example of Tau technology. The loss also forced the Tau to accelerate their development of new Stealthsuits; the new XV25 Stealthsuit was rushed into production ahead of the harder-to-produce XV22 Stealthsuit.