Even some canon is contradictory, allowing readers to choose for themselves what to believe. Partly that was intentional, even - to reflect how no-one in the setting truly knows what's going on.<br/><br/>For instance, the following statements are<em>both</em>true, according to canon:<br/><br/>1. No Sister of Battle has ever fallen to Chaos.<br/>2. There are entire groups of Battle Sisters that have fallen to Chaos.<br/><br/>I of course choose to believe the former.<br/><br/>Incidentally, it was cool to discover that one of the books basically answers the question on whether the Imperium is homophobic (in a setting where there are people who happen to be Chaos-worshipping psykic mutants). The answer is "No, they don't mind."