The Hellion War
The Hellion War began in 870.M33, when the Hellion Sector declared its secession from the troubled Imperium, after the wake of the anarchy that followed the War of the False Primarch and its aftermath. The Sector then bloodily attacked its neighbors and it became apparent to the Imperium that Hellion's rulers had become Chaos worshipers. Worse news followed as the Hellion Sector's millions of men-under-arms were corrupted as well and its worlds began producing Daemon Engines to use against the Imperium. The ever widening war caused by Hellion's rulers, soon swelled to ravage more than eighty inhabited Systems and uncounted billions died in the fighting. By the dawning of M35 however, the Imperium had reduced the Hellion Sector to little more than waste zones of barren worlds and dead Hive cities.