A body rune obtained in the Runespan is created by siphoning body esshounds or fleshy growths, requiring one rune essence and giving 23.5 and 46.2 experience respectively. This requires 20 Runecrafting.
Body runes are worth 0.3 Runespan points and can be used to cross conjuration platforms, mist platforms, flesh platforms and greater conjuration platforms. They will disappear and be converted into points if you leave the Runespan.
If you try to bank any runes or essence from Runespan you get the message "A magical force prevents you from banking this item."