Goron, what's the little chained bar below your health/mana bars?
Holy power. I've only tried it as protection, but it serves the same purpose of runic power for a DK.
Basically if you're a protadin, you use either Hammer of the Righteous or Crusader Strike 3x, then heal yourself instantly for a big amount. Or, you can do Shield of the Righteous for extreme damage and threat at 3 charges of holy power.