So, I was fighting a tension room of skeletons/zombies/ghuls while standing in a room tainted by evil, and they were dying very easily as usual, but everytime the hit it caused a critical. Actually had 3 hits in a row cause stunning. So I'm not sure if only chaotic creatures get this bonus to criticals, if it was bad luck, or only affects undead.
At the time was lvl 12 had 20/20 DV/pv. Not cursed or doomed.