Rotom is the very particular Electro / Ghost-type monster who stood out for his ability to disguise himself in machines and appliances. Also in Pokémon Legends: Arceus it is possible to meet Rotom specimens and make them assume the desired shape.
Finding the Pokémon Plasma is quite simple, but to do so you need to unlock access to the fourth area. After going to the Corona slopes, it will be enough to reach the two places where it usually appears: Piazza Prayer and Cresta Pietrinfila. There is also the possibility that groups of Rotom are the protagonists of massive extras, increasing the likelihood of finding a chromatic one.
Although Hisui is a technologically backward region, there is no lack of the possibility of making the monster take on a different shape than the classic Rotom Shape. The tools that allow metamorphosis can be purchased individually by the director of the Ginkgo firm, based in the Giubilo Village. In Pokémon Legends: Arceus there are all the currently known playable forms of Rotom, in particular: