Poltchageist only live in Kitakami, the region you visit during the Teal Mask DLC, so you have to own the DLC to find them or even receive one in a trade from a friend. They spawn in areas with ...

To add to the confusion, Poltchageist and Sinistcha are similar to Sinistea and Polteageist but they evolve ... flipped. Sinistea evolves into a Polteageist, but Poltchageist evolves into Sinistcha.