Who is the only Pokémon living in the wasteland before Ditto arrives in Pokémon Pokopia?

Professor Tangrowth is the only Pokémon living in the wasteland before Ditto arrives in Pokémon Pokopia.

Professor Tangrowth is a Tangrowth who has remained alone in the ruined world. After Ditto awakens and takes on a human-like form, the two meet and begin investigating what happened to the vanished humans and Pokémon.

Tangrowth gives the protagonist an important early purpose: restore habitats so Pokémon can return and thrive. As Ditto rebuilds the environment, more Pokémon appear, help with tasks, and teach moves that affect the world. The growing population also gives Professor Tangrowth hope that humans may eventually return.

The title “Professor” is part of this character's identity in Pokopia; it is not a conventional human professor directing a player character. Professor Tangrowth is a Pokémon researcher whose isolation reflects the game's post-apocalyptic premise and makes Ditto's arrival the turning point in the story.