Cleansing of Hive Thetus

Black Templars were called upon to aid in the extermination of a small-but-dangerous heretical cult on the planet Nevaria II. This menace was investigated by an agent of the Ordo Hereticus working within the overpopulated levels of Hive Thetus. Soon, this agent discovered the towering spyres of Thetus held a more sinister secret than anyone first suspected. A powerful and malevolent influence was behind the cult. Further investigation, along with a very costly covert strike by Deathwatch Space Marines, uncovered a powerful Broodlord at work. The creature had somehow managed to infiltrate and infect the minds of a large portion of Hive Thetus without anyone knowing. Years of crossbreeding the population had produced both physical and psychic abominations to Mankind.

It became obvious that Hive Thetus was becoming a staging ground for a dreaded Tyranid vanguard force. It had to be purged. The Black Templars stepped up to the challenge of returning the Emperor's Light to Hive Thetus with righteous zeal.

The Broodlord and its foul kin managed to anchor themselves deep within the Hive's blackened depths. The removal of this taint would take some considerable time and effort. The labyrinth of tunnels, accessways, ducts, and forgotten cities proved to be a deadly and unique battlefield. It was here that the Black Templars fought terrifying battles in cramped corridors against the Tyranid menace. Slowly and at great cost, each sector was cleared from the bottom up. Hive Thetus, and the entire world of Nevaria II with it, was made safe (relatively) due to the efforts of the Black Templars.