Bane (enchantment)

A Bane weapon excels at attacking one type or subtype of creatures. Against the right type of creature, a Bane weapon's effective enhancement bonus is better than its normal enhancement bonus. It also deals additional points of damage against the foe. This additional damage is untyped and cannot be reduced by energy resistances or any other form of damage mitigation.

Creature types
See also Damage vs Monsters by Type guide on DDOcompendium