Main Article: Runes#List
- Only increases base damage and that given by the primary attribute of the affected hero. Raw bonus damage is not increased.
- The hero's current main damage is checked periodically, and the bonuses adapted instantly.
- The buff is applied to invulnerable and hidden units.
- The buff of multiple Double Damage Runes does not stack, but refreshes the duration instead.
{{#set:
| title = Double Damage Rune
| image = File:Bottle (Double Damage) icon.png
}}