The shopkeeper can resist some forms of magic. The shopkeeper is fast. A specific theme will play when being near the shopkeeper.
Will buy all items from the player (except Worthless Piece of Glass), but does only offer fair prices on Wands, Potions, Scrolls, Spellbooks, Rings, Amulets -- a selection of which he also usually have for sale. He is also the only one to buy Food and Lamps, however, he does not give a very good price.
Like with the Gnome Jeweller, items sold by the Shopkeeper are unidentified unless you already know their effect.
- Be careful around Shopkeepers: they will become angry if probed, or hit/damaged by most weapon or spells. You can pay them 100 gold to make them peaceful after the first offense. Subsequent attacks will result in hostility, you can only neutralize him by using a scroll of taming (however cannot become tame). Stealing items from a shop will also result in a fine, probably dependent on the value of items stolen.
- A Shopkeeper can easily be 'tamed' if the player has a Werewolf as a Pet, since the Werewolf can be ordered to attack him, poisoning him with Lycanthropy after which he can be tamed with a Scroll of Taming or Lute of Charming.
- "Try before you buy"! Although they won't advertise it, Shopkeepers kind of allow you to sample their wares. This is particularly useful to identify their rings on offer: stand by the shop, pick unidentified rings from the shelves and try them on! (but don't go anywhere or you'll be considered shoplifting). Rings that modify your status or stats will get identified (levitation, invisibility, regen, strength, adornment, constitution, etc…). Then just "sell" back the (stolen) items and walk away with more knowledge, or buy the ones you really need. With a Wand of probing, Amulets can also be identified this way.
- You can steal from the shops by picking up the wares and teleporting away. This is most useful if you have some method to control the teleport. The shopkeeper will remain angry on your way back up the dungeon. You will feel very guilty about this, but there doesn't seem to be any ill effects.