Expert: Mr. Black, Tarant or Mr. Razzia, Caladon
Master: Albert Leek, Caladon (Sobbing Onion)
The quest here is simply to find the master, Albert Leek, and to do that you have to follow the clues from three notes. You’ll get the first note when you train to be an expert, and it should lead you to the Mushroom Inn, room 4 (in Caladon). There you should find a second note, and it will give you clues to look under the bed, put on the glasses you should find there, and then look at the portrait. You’ll receive a new location on your map -- a Mysterious Location (1586W, 1816S) -- and there, if you travel northeast, you’ll find a hollow tree stump guarded by several brute fangs. Brute fangs are nasty in groups, so be prepared before you go in. In the stump you’ll find the third note, and it will tell you to read the note again by the fireplace in the Mushroom Inn. So go back to the inn, read the note again, and learn that the master is named Albert Leek and can be found at the Sobbing Onion.
When you find Leek, he’ll introduce himself as “A.L.” but if you have a couple drinks with him, you’ll eventually recognize who he is, and he’ll give you training (plus a ring of silence). Note that the drinking might lower your prowling skill enough that you’ll have to wait until you’re sober again to train. Also note that it doesn’t appear as if you really have to get the notes. Once you get expert training you can just walk right up to Leek to train with him.