Andor's Trail

Demons, ghosts, and constructs (e.g. oozes, gargoyles, mudfiends) are immune to critical hits. It's hard to think of a single vulnerability that fits all of these.

Well, I doesn't have to be one. Why not two? Holy Water/crosses and the constructs is harder.

If you consider animated constructs as products of necromancy, then lumping them in with undead and demons a little easier. "Dispelling" damage?