Rules Index | GM Screen | Player's Guide

Chapter 9: Playing the Game / General Rules / Damage / Step 1: Roll the Damage Dice and Apply Modifiers, Bonuses, and Penalties

Increasing Damage

Source Core Rulebook pg. 451 2.0
In some cases, you increase the number of dice you roll when making weapon damage rolls. Magic weapons etched with the striking rune can add one or more weapon damage dice to your damage roll. These extra dice are the same die size as the weapon’s damage die. At certain levels, most characters gain the ability to deal extra damage from the weapon specialization class feature.