An effect type. A runic power channels the magic of runes that are specified in the power. Unless otherwise noted, using a runic power follows these rules.
Choose First: When a creature is going to use a runic power, it first chooses one of the runes in the power and then uses the power, applying the chosen rune’s effects at the time indicated in the power (after hitting with the power, for instance).
Rune State: The creature is then in the rune state associated with the chosen rune until it enters a new rune state or until the end of the encounter.
Published in Player's Handbook 3, page(s) 217, Rules Compendium, page(s) 119, 315.