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Freezing Touch (Su): A frostmourn's slam attacks deal an additional 2d20 points of cold damage (Fort DC X halves the damage). Similarly, any creature striking a frostmourn with natural attacks or unarmed strikes or grappling a frostmourn suffers 2d20 points of cold damage (Fort DC X half). frostmourn's freezing touch is a death effect, so raise dead will not restore a creature slain in this manner to life (although ressurection or similar magic will). The save DC is Charisma-based.
Frostbrittle (Su): Any weapon that strikes a frostmourn has its hardness reduced by 5 for 10 rounds, thereby increasing the effectiveness of sunder attempts against the weapon. In addition, rolling a 1 on an attack with the targeted weapon causes it to take damage equivalent to the amount it would have dealt on a successful hit.