The rune system is the resource system used by death knights, much as mana, energy, or rage are used by other classes or focus used by hunters' pets. The death knight's rune system consists of two very distinct but complementary resources: runes and runic power. Some of the death knight's spells and abilities require spending runes; others require his or her having generated through battle a certain level of runic power. Every death knight who has not recently been in combat enters a fresh combat situation possessing six expendable runes but no runic power. Only by spending some of these runes (each of which regenerates after ten seconds) on battle spells may the death knight thereby acquire and incrementally build up for a short time runic power, which in turn he or she may draw on for other spells. The death knight's rune system thus combines characteristics of those classes relying for combat powers on depleting-but-renewable resources — such as mana (mages, warlocks) and energy (rogues) — with those classes relying for combat powers on resources generated solely through battle itself, such as rage (warriors).
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.
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 Stike 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.
- 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.
Runic power is an extra resource that builds up as the death knight uses his or her abilities, displayed as an empty bar that fills up with a light sky blue color similar to rage under the death knight's health bar. Generally, offensive single rune abilities generate 10 runic power and offensive multi-rune abilities generate 15 runic power. Additionally, Empower Rune Weapon and Horn of Winter generate runic power without costing runes. Talents can improve the runic power generation of some abilities and allow runic power to be generated in other ways. Death knights start with maximum 100 runic power but that can be increased up to 130 through Runic Power Mastery. As with rage, runic power gradually diminishes when not in combat.
Rune abilities by cost
Single rune abilities
|Cost||Frost + Unholy||Blood + Frost + Unholy|
Cost changes to existing abilities:
- Death and Decay: 1 Unholy
- Howling Blast: 1 Frost
- Scourge Strike: 1 Unholy
Runic power abilities
Developers said at BlizzCon 2007 that they didn't want the new class to use the traditional resource systems because they wanted the death knight to have a different style of play. They stated their intention was for the death knight to use a mixture of spells and melee in close combat. Because of this, a system that didn't specifically rely on either mana or rage was more appropriate.
During the 2008 WWI, it was noted that the original runes were replaced because they were too complex to show them refreshing inside the character's portrait bar.
- Hotfix (2009-06-02): "Runic Power costs will no longer be lowered by abilities intended to lower mana costs."