Rune Magic
Rune Magic is a tradition of Magic that is known to have existed but has largely been lost as of the time of Mythic Europe.
Is it detailed in pages 133-143 of Ancient Magic. It is practiced by the Vitki, detailed in Hedge Magic Revised Edition. If the Order of Odin actually exists, it can be expected to have knowledge of Rune Magic as well.
In Fourth Edition, the Vitki and Rune Magic were detailed in Ultima Thule.