DKs will not use mana, energy or rage, they will use runes. They can insert either Frost runes, Unholy runes or Blood runes into their weapon. They can have a maximum of six total runes at the same time. Different spells and abilities will use runepower to cast. The runes will then be put on a cooldown.

For example: You have three Blood runes and three Unholy runes in you weapon. You then cast a spell that requires two Unholy runes and one Blood rune. Those runes will then be put on a cooldown and you will have two Blood runes and one Unholy rune left to use.

How long this cooldown will be is unknown and will probably change with different runes.

EDIT: Some spelling.

How Do tou Know that? Who would for sure know that, besides Blizzard people?I really think ur Geussin about Runes. That is sad