The Pokémon Trainer is in essence the player themselves. Throughout the evolution of Pokémon games, the Pokémon Trainer has taken on many different shapes and forms. The trainer is customizable down to name, gender, and at times, birthdays. In each Pokémon game, the trainer's main goal is to catch and train Pokémon in order to compete against other trainers and gym leaders in order to become the greatest Pokémon Trainer of them all, the Pokémon Champion. In order to become Champion, a trainer must challenge and defeat the Elite Four, the best trainers in the league, followed by the current Champion. In order to even make this challenge, a trainer must have all eight of the league badges, obtained by defeating the eight sanctioned Gym Leaders. This is a monumental goal indeed. Another main goal of the average Pokémon trainer is to collect all of the Pokémon in the game (currently at a total of 493 Pokémon) in order to complete the trainer's Pokédex and become a Pokémon Master.
Pokémon Trainers of Each Generation
With each new Pokémon game, there is a new version of the Pokémon Trainer in which you can change the name that fits you. Up until the release of Pokémon: Crystal Version, the player was only able to play as a male character. Each subsequent iteration allows the player to choose a male or female character to go on the Pokémon quest.
The Pokémon Trainer of the Kanto Region, whose canon name is Red (referred to as "Ash Ketchum" in the anime), hails from Pallet Town, which is also where Professor Oak's Lab is located. In Red and Blue Version, the Pokémon Trainer is able to choose between Bulbasaur, Charmander, and Squirtle.
He has a rivalry with Blue (a counterpart to the trainer is the character Gary Oak in the anime), grandson to Professor Oak and a childhood friend that becomes competitive and rude, who will choose the Pokémon that has an elemental advantage against yours (i.e. if you choose Charmander, your rival will choose Squirtle).
In the Yellow version, The only starting Pokémon is Pikachu, and the rival's is Eevee. In this version, Pikachu follows his trainer around Kanto, but refuses to evolve into Raichu. The Yellow Version Pokémon Trainer most resembles Ash Ketchum of the anime series. While attempting to become the Champion, the trainer will also work to spoil the efforts of Team Rocket. A remake of Pokémon Red and Blue, titled Fire Red and Leaf Green, allows the player to choose between a male or female character.
The Pokémon Trainer of the Johto Region, Gold, comes from New Bark Town. This Pokémon Trainer receives his Pokémon from Professor Elm soon after moving into town, and has the opportunity to choose Chikorita, Cyndaquil, or Totodile.
Unlike Pokémon Red/Blue, and Pokémon Yellow, the Pokémon Trainer's rival is a thief, Silver, who coincidentally steals the Pokémon that has an elemental advantage against your own.
A new introduction in the Crystal Version is the option to choose whether your trainer is a male or female.
In the manga, the female trainer's name is Kris. Just like the first generation of Pokémon, This trainer will also work towards spoiling Team Rocket's plans. An interesting twist in this game is that after you go through the Pokémon League in the Kanto Region, you will have an opportunity to face Red, who apparently became a recluse after he lost the Champion title.
The Pokémon Trainer of the Hoenn Region are Brendan and May.
Depending on the chosen gender, the specified Pokémon Trainer recently resides in a small home in Littleroot Town. The trainer initially finds Professor Birch being attacked by a wild Pokémon, and must choose one of three Pokémon ( Treecko, Torchic, and Mudkip) in order to save him. Once the protagonist saves Professor Birch, he'll grant them his thanks by allowing the Pokémon Trainer to keep the selective Pokémon chosen during their first battle.
The rival in this game is the son/daughter of Professor Birch, which is the unchosen gender of your trainer. Unlike previous rivals, this rival acts more like a friend who just wants to see how much the player has improved. This trainer will also work to spoil the plans of Team Magma (in the Ruby Version) or Team Aqua (in the Sapphire Version).
Also, in order to save the land from either a drought (caused by Groudon and instigated by Team Magma) or severe rainstorms (caused by Kyogre and instigated by Team Aqua), the Pokémon Trainer must catch Groudon or Kyogre to bring the weather back to normal. In the Emerald Version, both Team Magma and Team Aqua are villains in the game. While both still unleash Groudon and Kyogre, the Pokémon Trainer must summon Rayquaza instead in order to bring peace to the land.
The female Generation III trainer design was used for the character May (Haruka in Japan) in the Pokemon anime series.
The Pokémon Trainer of the Sinnoh Region, either Lucas or Dawn, depending on their gender, is originally from Twinleaf Town. The starting Pokémon in this game are Turtwig, Chimchar, and Piplup, and they are chosen in a more traditional manner than in Generation III, with the character picking one after being offered their choice by a Professor.
Whichever gender you don't choose ends up as a supporting character in the game, who picks the type-advantage starter, but like G-III, this character isn't so much a rival as a friend who genuinely enjoys your occasional battle.
The female Generation IV trainer design was used for the character Dawn (Hikari, in Japan) in the Pokemon anime series.
Generation V (Black and White)
The Pokémon Trainers of the Unova Region, Hilbert (male) and Hilda (female) are from Nuvema Town. Unlike previous games where the protagonists are children, the protagonists of Black and White are teenagers. The starting Pokémon are Snivy, Tepig, and Oshawott.
Black 2 and White 2, the second pair of Generation V games, also take place in the Unova region, set 2 years after the previous games and with new protagonists, Nate (male) and Rosa (female), from Aspertia City.