That’s because the original games, Pokémon Pearl and Diamond, had a unique problem: There are not a whole lot of fire Pokémon to pick from.
When I picked Turtwig — the adorable turtle-like grass-type — as my starter Pokémon in Pokémon Shining Pearl, I wondered if I had signed a death-wish.
When the original Diamond and Pearl games came out, players who didn’t pick the fire-type starter, Chimchar, had only one other option if they wanted to train a fire-type — Ponyta.
This new feature allows the game to bring on more Pokémon from outside the original Sinnoh Pokédex from the original Diamond and Pearl.