The Dennar IV Suppression was an Imperial military campaign carried out by the Howling Griffons Space Marine Chapter against Chaos Cultists on the Agri-World of Dennar IV in 109.M40. During their long search for the Word Bearers Chaos Space Marine warband of Deklamus the Vaunted, the Howling Griffons 3rd Company under Captain Penvath Joachim responded to a planetary distress call from the world of Dennar IV in the Sangramentia Sector. This important supply world had succumbed to rot from within as the worship of the Ruinous Powers took root amid its flenser-cults and cult-clans. As the Howling Griffons descended on Dennar IV, they found only a handful of its city-states holding out against the horde of Chaos Cultists and daemon-possessed madmen, their walls packed with refugees fleeing the tide of mass-murder that had engulfed the planet.
Vastly outnumbered, the Howling Griffons deployed to the savannah, and wielding their superiority in armour and air power to stay mobile and spearhead assaults against the Heretics, smashed the cult forces in great scything sweeps before driving onwards to relieve the city sieges. The Loyalist inhabitants of Dennar greeted the Howling Griffons as divinely-sent saviours, and gladly rallied to aid them in liberating their world from the dark forces that assailed it, selling their lives alongside the Space Marines. The remaining campaign was bloody and ruthless, ever-afterward casting a nightmarish pall over the memory of Dennar's people. Since this victory, the Howling Griffons have maintained a lasting oath to protect the planet and the memory of the many martyred there for their loyalty to the Emperor, while the people of Dennar IV have kept faith with their saviours in providing them with victuals and the pick of their youth as Chapter recruits.
- Imperial Armour Volume Nine - The Badab War - Part One, p. 126