In order to become a maestro, you must pass the Test of Maestro. Iron Gate's Lockirin who administers the test says that you must obtain and bring back recommendations from three other elders. Will you indeed be able to obtain recommendations from the three Dwarven elders who are known to have very high standards?
Talk to Corpse Of Kamur, then face the wall behind him, notice how it looks a little odd? This is a false wall, go ahead and walk through it and follow the path. The next room has Quest Monster Evil Eye Lord.