A list of the locations of Pokémon Gengar's fixed-point exchange NPCs. Many players may not know where Gengar is exchanged in the game. Here is a detailed introduction for your reference.
Gengar exchanges NPC positions at fixed points
There is an NPC on the small map of Niangguang City (Qishu). You can exchange the Snapping Sea Urchin for her Ghost Stone (unlike Diamond, which does not carry the Unchangeable Stone). After the exchange, she can directly evolve into Gengar.
Additional information: Snapping sea urchins can be caught at the beach on the road to Nianguang City.
