Invasion of Tsadrekha
The Hive World of Tsadrekha was cut off as a result of the formation of the Great Rift. As the world faced the machinations of Chaos, a Psyker emerged with enough power to act as a beacon to allow for contact with the greater Imperium despite the loss of the Astronomican. However, this beacon also drew an Alpha Legion warband known as the Unsung.
Battling through the Imperial defenders, the Unsung nearly were successful in their plan to claim the beacon and corrupt it for the Ruinous Powers. However their plans were interrupted by Kharn the Betrayer and his Butcherhorde, which had also been drawn to the planet by the beacon. Another warband of Emperor's Children under Excrucias the Flawless arrived, and was able to summon the Keeper of Secrets Sl'eth'kryphyr. Another group of World Eaters of Khordas the Slaughterer also arrived on world.
The infighting between the Chaos forces allowed Imperial Fists under Captain Paetrov Dysorian to arrive on Tsadrekha and turn the tide. At the climax of the battle, Saint Celestine herself appeared and slew Sl'eth'kryphyr. After dispatching the Keeper of Secrets, Celestine engaged Kharn in a duel. Despite her best efforts, Kharn killed the Living Saint but her efforts to save Tsadrekha were not entirely in vain.