Tangrowth appears as the lone remaining resident when Pokémon Pokopia begins.
The game’s setting describes a world where people and Pokémon once lived happily together, but the environment has withered and the humans are gone. The only remaining resident appears to be a lone Tangrowth.
This opening situation establishes the game’s central purpose. A peculiar Ditto awakens after a long slumber and begins restoring the desolate land, using transformation skills and newly acquired crafting abilities. Other Pokémon gradually become part of the rebuilding effort.
Tangrowth is easy to confuse with other plant-associated Pokémon, especially Torterra or Venusaur. However, the game’s official description specifically identifies Tangrowth as the solitary resident encountered at the start. Its vine-covered appearance also fits the overgrown, damaged world.