I would also suggest that they frequently make pacts with one Runious Power or another prior to entering battle, calling upon the favour of a god in return for the souls they slay. They do not favour one god over the other however, preferring to worship the 4 gods as a single entity.Combat Doctrine: Use surgical strikes by Raptor teams to take out key objectives before dropping a main force to engage the enemy forces and terrorise the population. Use all deamons/cultists shamelessly. Have a particluer hatred (and take delight in killing) for Preists, Inquistitors, Chaplins etc as they see them as ambassadors of the Emporer that never forgave them. They hate Saints even more due to it was the fault of one of them that they fell from favour. They are kinda like a cross of Word Bearers and Night Lords. They favour the use of Close Combat and short range fire fights as it allows them to see the enemy and personally punish them for thier (perceived) betrayal of the Chapter.