On a critical hit, the weapon adds a weapon damage die of the listed size. Roll this after doubling the weapon's damage. This increases to two dice if the weapon has a greater striking rune and three dice if the weapon has a major striking rune. For instance, a rapier with a greater striking rune deals 2d8 extra piercing damage on a critical hit. An ability that changes the size of the weapon's normal damage dice doesn't change the size of its deadly die.

This weapon becomes more dangerous as you build momentum. When you attack with it more than once on your turn, the second attack gains a circumstance bonus to damage equal to the number of weapon damage dice, and each subsequent attack gains a circumstance bonus to damage equal to double the number of weapon damage dice.

Natural attacks with this trait can be used to attack creatures up to the listed distance away instead of only adjacent creatures. Weapons with this trait are long and can be used to attack creatures up to 10 feet away instead of only adjacent creatures. For creatures that already have reach with the limb or limbs that wield the weapon, the weapon increases their reach by 5 feet.