Which Pokémon generation is the oldest represented in Pokémon Pokopia’s roster?

Generation I is the oldest Pokémon generation represented in Pokémon Pokopia’s roster.

The game features 300 Pokémon selected from Generations I through IX. Since Generation I is the first generation in that range, it is the oldest represented group. Generation IX is included too, but it is the newest generation in the stated span rather than the oldest.

Generation I introduced the original Pokémon games and the first group of species, including familiar names such as Pikachu, Bulbasaur, Charmander, and Squirtle. Later generations expanded the series with new regions, characters, mechanics, and Pokémon. Pokopia’s roster draws from that broad history instead of limiting itself to one region.

The wording “oldest represented generation” refers to the generation’s position in Pokémon history, not the age of an individual Pokémon or the order in which a player encounters it. The correct choice is therefore Generation I, the beginning of the game’s I-through-IX selection.