Newly promoted to his position, Nightwind was chosen to lead the Tau's forces on the world of Kappa Mortis, as the Crusade was officially ending, on a mission of dire importance. There an Ultramarines strike force, led by Captain Severus Agemman, was trying to reach the crash site of a Aquila Lander filled with captured Tau tech. Charged with stopping them, Nightwind led his forces to the crash sight, before the Ultramarines and prepared an ambush. As the Ultramarines reached the Aquila, Nightwind gave the order to attack and what followed was a brief and bloody battle. Though Nightwind's forces inflicted heavy causalities among the Ultramarines, including severely wounding Severus, they were unable to stop the Space Marines from escaping with a XV15 helmet. This failure would force the Tau to accelerate the development of the XV25 Stealthsuit.