Tangrowth is the only Pokémon living in the wasteland when Pokémon Pokopia begins.
The protagonist awakens in the Withered Wasteland, a world where the environment has deteriorated and humans have disappeared. Tangrowth is the lone resident there, living by itself before Ditto arrives and begins restoring the area.
This Tangrowth later becomes known as Professor Tangrowth. The character serves as an early guide and explains that the other humans and Pokémon vanished long ago, although Tangrowth does not know where they went. The mystery gives the rebuilding project a narrative purpose beyond decoration.
As Ditto restores habitats, more Pokémon gradually return to the area. They can help with tasks, teach useful moves, and contribute to the revival of the landscape. The increasing Pokémon population also gives Professor Tangrowth hope that humans might eventually return.
Tangrowth should not be confused with the many Pokémon encountered later. Slowpoke becomes important because its yawns bring rain, Onix is trapped in a cave, and Kyogre helps summon a larger rainfall. Tangrowth is the initial resident and the story’s first major guide.