Dodskrigaren said:
See, your saying I said they exist in the 41st milleum according to cannon, something I never said. Just said they could. Theres /no/ cannon either way to resolve the issue, at which point, the arguement that they exist, or that they don't, is a matter of opinion and personal taste. Chill a little and dial it back man.
Again, you're mistating the argument. The existing canon contains absolutely no mention of the Sisters, especially in areas where they would be logically employed. There is no canon support for them existing in the 41st Millenium.
Two sidenotes:
1) Deathwatch is at the printers! Rejoice! I command it!
2) The Sisters origins are curious. The secular Empire that the Emperor was forging would not have created them. Only female Untouchables? Sworn to silence when they're working with others to harvest and manage psykers or provide anti-psyker battlefield support? That's not the rational way to go about things. It seems more likely that they were some kind of pre-Imperial monastic order that was incorporated into the larger fabric of the Imperium. That would be an interesting story to tell.