Which fictional Pokémon researcher does Ditto meet in Pokémon Pokopia?

Ditto meets Professor Tangrowth in Pokémon Pokopia.

Professor Tangrowth is a Tangrowth who has taken on the role of a researcher in the abandoned world. He studies the environment and investigates the mystery of why humans and Pokémon have disappeared or left the region.

The meeting gives the story a clear purpose beyond construction. Ditto is not merely decorating a settlement; together with Professor Tangrowth, it helps restore habitats so Pokémon populations can recover. Their work gradually reveals information about the world's past and the fate of humanity.

Professor Tangrowth should not be confused with the recurring human professors from the main Pokémon games. Professor Oak, Elm, and Kukui are human researchers associated with different regions. Professor Tangrowth is a character created for Pokopia and is notable because he is himself a Pokémon conducting research.