Undead supposedly take double damage from blunt weapons.
Please note that this is not true of all undead. If it effects the NPC you are playing, it will be on your NPC stat card. Therefore, often times a PC would not know whether or not you take double from blunt weapons (or silver / magic / etc). For that reason, the NPC is responsible for keeping track of what effects them. Granted, if you're a skeleton who gets hit in the back with a mace, you may not know it was a blunt weapon that hit you, but you should do your best to keep track in situations like that.
Sean
