The Merchant
Not anchored to any tile — over a full session he circuits the entire connected map's perimeter.
Movement
Activation: Moves once during the Monster Phase, after all monsters have activated.
Direction: 1 space clockwise along the perimeter. Loops his current tile's 3-space perimeter (A→B→C→A) unless the next step crosses into a neighboring tile, in which case he crosses. He never enters any center space.
Travels the map: Not anchored to his starting tile — over a full session he circuits the entire connected map's perimeter, tile by tile.
Blocked: If a monster occupies his destination space, he does not move that phase.
Can't activate: If a monster is in the Merchant's current space, heroes cannot trade there until it's defeated or leaves.
Trading
Blocked: If any monster occupies the Merchant's space, trading is suspended.
Inventory: The top 5 cards of the shuffled Item deck are placed face-up beside the Merchant at game start. Sold items are not replaced.
Buying: Spend 1 action while on his space: pay the gold cost of any available item.
Selling: Any hero on his space may sell any item back for half its cost (rounded up), free action — always available, no item required.