Runes are unique items that spawn in the river at points on the map every 2 minutes (starting at 0.00). Originally, one rune would spawn every two minutes, but as of balance patch 6.82 two runes spawn on the map every two minutes, one of which is always a Bounty Rune.
They give the person who activates it a special power for a short period of time (the power varying depending on the particular rune that spawns).
Runes can also be picked up and stored in a Bottle (this process is called 'Bottling'). This has two effects: 1) you can save the rune for up to 2 minutes without being forced to use it. 2) it refills your bottle, so when it is eventually activated you will have 3 bottle charges left over afterwards.
The following runes can spawn in the game:
Bounty Rune
The newest rune in the game, it was added in 2014's Rekindling Souls update.
One Bounty Rune always spawns every two minutes and grants the person who picks it up (or Bottles then uses it): 1) 50 experience and an additional 5 experience per minute, and 2) 50 gold and an additional 2 gold per minute.
The only exceptions to this rule are the first rune spawns. These are both Bounty runes and grant double the value (100 experience and 100 gold).
Double Damage
When activated, the Double Damage rune gives the hero and any controlled illusions within 500 AoE +100% attack damage for 45 seconds.
This only affects attack damage, not spell damage, and does not take into account pure damage items (such as the Divine Rapier).
Haste
When activated, the Haste rune gives the hero a Haste buff (+100% movement speed and immunity to movespeed slow) for 30 seconds.
This will usually cause the hero to move at maximum speed.
Illusion
When activated, the Illusion rune creates two illusions of the hero who activated it.
These illusions last for 75 seconds, deal 35% damage, and take 300% damage.
Invisibility
When activated, and after a 1 second fade effect, the Invisibility rune gives the hero invisibility for 45 seconds.
Invisibility is broken if the hero perform actions such as attacking, using items, or using spells.
Heroes can also still be spotted by anything with True Sight (such as towers or sentry wards), but will not lose invisibility.
Regeneration
When activated, the Regeneration rune gives the hero 100 health per second regeneration and 67 mana per second regeneration for 30 seconds.
The effect ends if the hero takes damage or if both their health and mana reach their maximum.
