There's quite a niche in rogue-like weapons that can do anything significant to undead. I propose a sai that is focused on dealing with undead for dex-characters. It's otherwise quite redundant against non-undead. It Would Be Cool. why sai? sai does bludgeoning damage, and bludgeoning damage is usually more effective against undead
Sai - Severance
runic
bonus damage type - piercing
+3 attack bonus
+5 attack bonus vs undead
damage bonus: 8 bludgeoning damage vs undead
damage bonus: 2d8 positive energy damage vs undead
damage bonus: 2d6 magic damage vs undead
(no innate keen because undead are crit immune)
+5 will save against fear
+2 AC deflection bonus
+5 AC deflection modifier against undead
special property - cannot be wielded by vampires and palemasters, no UMD bypass.
requirement: rogue, vigilante, liberator, swashbuckler, monk.
increased UMD requirement 40
level requirement 21
smithing - crafting:
4 mithril ingots
3 silver ingots
1 moonstone
1 sunstone
8 holy water
1 scroll of undeath's eternal foe