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The upgraded Pokedex -- Professor Oak's latest model that can identify Pokemon from every known region, the ostensible reason for the entire Sevii Islands journey.
The National Pokedex is what Professor Oak claimed he needed Red and Blue to deliver. In truth, he wanted to retrieve their existing Pokedexes, upgrade them to National Mode capable of cataloging Pokemon from all regions, and return them. The upgrade itself is a minor plot point -- the journey it necessitated is what matters. Oak used the Fame Checker to send cryptic messages guiding the Pokedex holders to the Sevii Islands, where the upgrade could be completed using data from Celio's Network Machine. After his rescue from Trainer Tower, Oak completed the upgrades and distributed the new National Pokedexes to Red, Blue, and Green. The devices represent Oak's belief that knowledge -- the systematic cataloging of every creature in the world -- is the foundation of everything else.
A sleek handheld device, more advanced than the original Kanto Pokedex. Its screen is larger, its database vastly expanded, and it bears the marks of Oak's meticulous engineering. Each of the three main Pokedex holders receives their own upgraded unit.
Also known as: National Pokedex, the upgraded Pokedex, National Mode