Steel is forged by striking at it with a hammer in the forge, shaping it into new forms. The warhammer too shapes the enemy's armour, using their innards as the anvil, into a laminated coffin.
EFFECT:
Hammers ignore Armour Saving Throws. Instead, each point of ARM the enemy possesses reduces a hammer's Damage Dice Rolls by -2 (10d3 -> 8d3).
If at least half of the dice rolls strike their maximum value (for d4, that is a 4) inflict a Critical Hit. However, hammers cannot inflict Severe Bleeding. Instead, on a 4 or 5, inflict Crippled.