Ever since the release of Pokemon Red & Blue more than a quarter of a century ago, mainline Pokemon games have always come in pairs. Some see this as a cynical cash-grab from Game Freak and Nintendo, and while it's possible that there may be some element of truth to this, it also serves another purpose. Each pair of games features version-exclusive Pokemon, meaning that players will need to trade with their friends in order to complete their Pokedex. Unsurprisingly, perhaps, this is once again the case with the series' latest installments, Pokemon Brilliant Diamond & Shining Pearl.