Desumasu, known as Yamask in English, is a Ghost-type Pokémon from the Pocket Monsters (Pokémon) series. Introduced in Generation V, Desumasu is known for carrying a mask that represents its face from when it was human. This Pokémon is mainly found in ancient ruins and is deeply tied to themes of memory and loss. In the series, Desumasu often plays the role of a mysterious and sometimes sorrowful companion, reflecting its spectral origins and unique lore.