Board Thread:Warhammer 40k General Discussion/@comment-6134883-20130417202949/@comment-3580035-20130508070651

Did anybody look at the link I posted further up? The Grey Knights killed the Sisters because they had been tainted by the Bloodtide. However, since the sisters needed to be killed but were still acting normally, their blood was considered pure enough to use afterwards.

However! The key point is that the Sisters were going to be killed one way or another, whether in or after the conflict. Consider it a good thing that they were useful after they were killed.

Btw, Grey Knights nevertheless murder whole Impearial populations who have seen Daemonic incursions. (although this is NOT Matt Wards fault).