Morangias said:
Grey Knights willing to go Xanthite are imaginable. A letdown for many, but it can make sense.
Grey Knights going full Xanthite yet remaining incorruptible make no sense at all. You dabble in Chaos, Chaos dabbles in you.
Grey Knights already use sorcery since they use blood magic and great spells based on the sacred numbers of the great powers of chaos. The codex admits that thier warriors are steeped in the same madness as they must use the weapons of the enemy to combat it. They are the biggets heretics and hippocrites of all. I hate that as ignores one of the themes of 40K which is the weapons of the enemy corrupt always. Its a big change from what they used to be.