Quote Originally Posted by Telonius View Post
Technically, that threat range could have happened in 3.0, but would have required Disciple of Dispater, a rapier, and the Improved Critical feat.
3.0 has both Keen and Improved Critical stacking. 18-20 is the Rapiers base range, either would increase it to 15-20 (+100%) and the other +100% would drop it to 12-20.