The death knight has access to three different types of runes: Blood Blood, Frost Frost, and Unholy Unholy.
These three types of runes are also the names of the death knight's three respective talent trees.
Before casting any spells, the death knight has three pairs, totaling six runes. Different abilities and spells consume different types and amounts of runes and, when used, will place the corresponding rune on a 10 second cooldown (9 seconds if in Unholy Presence, having Improved Unholy Presence). Some abilities are able to refresh certain runes; Empower Rune Weapon will refresh all of them.
There is also a fourth type of rune, which acts as any of the main rune types, the Death Death Rune.
The death rune can be created by using the skill Blood Tap or through the following talent upgrades:
Within the Blood tree, the talent Death Rune Mastery will give you a 33-100% chance to convert a Frost and Unholy Rune into a Death Rune after landing a hit with Death Strike or Obliterate. When procced, this will give you two Death Runes.
The Frost tree talent Blood of the North gives you a 30-100% chance after hitting with Blood Strike or Pestilence that a Blood Rune will become a Death Rune when it activates.
The Unholy tree talent Reaping provides a 33-100% chance to convert a Blood Rune into a Death Rune after hitting with Blood Strike or Blood Boil.
NotesEdit
Ten seconds may sound like a lot, but it actually isn't. If you only use abilities that require only 1 rune, you will have approx. 2 seconds left when using up all runes, sometimes even less if you've acquired death runes, and after that you also have a good amount of runic power accumulated.
When a death rune temporarily replaces your frost, blood, or unholy runes it will be used as a last resort if no main rune is available for the ability you want to use. Death runes are not used in the order you receive them; death runes which replace blood runes will be used before death runes which replace frost or unholy runes, and death runes which replace unholy runes will be used before death runes which replace frost runes.