There is a set of runes not used in the common parlance. They are not used in seiðr or any galdr known. They are simply known as the Runes of Power. Once you learn them, they indelibly mark themselves upon your being and affect you in ways that are often unpredictable. Without a doubt, they all bring power, but power at a cost, for they tap into the very heartwood of Yggdrasil itself. It is said that the runes that are known are not the runes that Odin learned upon the Tree, but rather these Runes of Power.
The Runes are not self-contained, it is said. You must be able to make a connection back to the source of the power, Yggdrasil, and thus come from the primordial powers. Thus, if Surtr hands out an Eld Rune to a lieutenant, Surtr must be alive for the Rune to have power. Indeed, the lieutenant can bestow the knowledge of the Rune on another, but it will lack power until Surtr acknowledges the connection, and will lose power if the line is broken (for instance, if the lieutenant dies).
Each power puts their own limits on how much may be tapped, but it is not uncommon for distribution of a Rune to be limited to one person per year.