all the way at the end . . you must work your way to the last room in the pit . . this used to be the Gharik's Forge dungeon in the original game. Move the bridge, cross over the big area, go down the elevator, fight the oozes and mini-dragons. walk up the long ramp, cross another bridge and you will find that last room wher the staff of Merlin is to be found in a chest.You cannot have sold it as it is a quest item and not saleable.
You cannot be promoted without it and later, without the second mage promo (adept) you cannot master air magic.
Don't try to take a short cut and edit your characters as you may cause the converter to Part 2 to fail.