Critical Strike
You land a lucky or precise blow, and hit a target in a vulnerable location. This is called a Critical Strike. Whenever you hit with a Weapon Attack, you roll a percentile (also known as a d100) to determine whether or not the hit was a Critical Strike. If your roll is less than or equal to your Critical Strike Chance, you deal additional damage on the attack equal to your Critical Strike Damage. You can calculate your Critical Strike Chance and Critical Strike Damage as follows. You can look up the Base Critical Chance and Crit Damage per Rank for your weapon on the Melee Weapon and Range Weapon tables.
Critical Strike Chance = Base Critical Chance + Physical Rank
Critical Strike Damage = Critical Damage per Rank x Physical Rank