From Dota 2 Wiki
Main Article: Runes#List
- Reduces the cooldown/replenish time of all spells and items.
- Affects cooldowns of active and passive abilities.
- Visually reduces the cooldown of , but does not affect it.
- Does not affect and ’s fade delay as well as 's certain crit/evasion timers.
- The cooldown reduction is not updated dynamically. Only abilities cast while having the buff get their cooldowns reduced.
- Stacks multiplicatively with the cooldown reduction of .
- Stacks additively with other sources of percentage cooldown reduction.
- Reduces all mana loss on the hero, including mana burning or draining effects.
- All reductions are reflected in the ability tooltips.
- Stacks additively with other sources of mana loss reduction.
- The buff of multiple Arcane Runes does not stack, but refreshes the duration instead.