Tangrowth is the lone Pokémon living in Pokémon Pokopia's wasteland at the start.
When Ditto awakens, the world has withered and humans are gone. Tangrowth is described as the only remaining resident of the wasteland, giving the opening setting a quiet, post-apocalyptic atmosphere. Tangrowth later becomes known as Professor Tangrowth.
The character helps establish the game's central goal: restore habitats and bring life back to a deserted world. As Ditto builds structures, grows plants, and attracts Pokémon, the empty landscape gradually becomes a shared community.
Tangrowth is easy to confuse with other Grass-type or physically imposing Pokémon. However, the story specifically identifies Tangrowth as the first resident Ditto meets and the character who explains the missing humans and the work of rebuilding.