User blog comment:Supahbadmarine/User Learning Lab/@comment-9465750-20120718184204/@comment-3993996-20120718184817

Warp exposere probably plays a part. Somtimes it may be down to gifts (such as Lucius coming back to life, Nurgle worshipers being immune to a lot of harm, Khorne keeping Kharn alive during the Horus Heresy, etc)