User blog comment:Supahbadmarine/Official Canon Policy/@comment-5571814-20130219062628/@comment-5571814-20130224001010

5. I personally would like to see something from the Dark Age.

6. This one is tough. It would take a majorly traumatic event to make chapter embrace any other ideology, especially a xenos one. I suppose one way would be to have them be excommunicated as traitors for some reason, but even that would have to be very severe.