Hidden down below Sanctuary, give the wings of the couatl (from Rune Graveyard) to the Nefarious Couatl. You need to kill (or have an Archon kill) the two mobs in the area to get the couatl to come out.
Note: All the rooms toggle between LPK, NPK, CPK, no magic and will repop dizzy quickly if dispelled.
For exhibiting true altruism towards the powers of Dira, the Powers grantedthee a Mark. You have been granted The Mark of Air! You gain 43 practices!