Purging of Yddylia
After a string of strikes by Biel-Tan against the Garravissima Sub-Sector proves impossible to stop, Deathwatch forces from Fort Ajax were deployed to hunt the aliens. They eventually descended on the Maiden World pf Yddylia at the height of summer and set the world aflame. The Exodites of the planet fought hard to repel the Space Marines, but are overwhelmed and call for reinforcements from Biel-Tan. The Eldar reinforcements promptly arrive, but within a week the Autarch leading the expedition is killed by Deathwatch assassins.