Generation IV

Generation IV in the Pokémon franchise, is a term used to describe the fourth set of games and Pokémon introduced into the series. The Generation IV games introduced a number of advancements including new Pokémon, moves and gameplay features.

Chronologically, Diamond, Pearl and Platinum take place in the same timeline as Generation II.

Starter Pokémon
As with the other main series Pokémon games, a new set of starter Pokémon were introduced for the fourth generation. Continuing with tradition, these Pokémon are a Water-type, Grass-type or a Fire-type. They include Piplup (Water), Turtwig (Grass) and Chimchar (Fire).

In the Gold and Silver remakes, Pokémon HeartGold and SoulSilver, the starter Pokémon will remain the same. They include Totodile (Water), Chikorita (Grass) and Cyndaquil (Fire).

Gym Leaders and the Elite Four
Generation IV introduced a new set of Gym Leaders and the Elite Four in the Diamond, Pearl and Platinum games. All of these trainers specialize in a specific type of Pokémon and are key to progressing through the game. The HeartGold and SoulSilver Gym Leaders, Elite Four and Champion will remain the same as their predecessors.

Pokémon Champion
In Pokémon Diamond, Pearl and Platinum, the Pokémon Champion is Cynthia, a woman that helps the player on various occasions. The Champion in HeartGold and SoulSilver remains the same as Generation II, which is Lance, a former member of the Elite Four and the man who helps you take down Team Rocket.

Antagonist
In Pokémon Diamond, Pearl and Platinum, the main antagonist is Team Galactic, whose objectives is to create a new world.

In Pokémon HeartGold and SoulSilver, the main antagonist is Team Rocket. They want to re-assemble their organization after Giovanni disbanded it after being beaten by Red.

Trivia

 * All the Sinnoh starter final evolutions have a second type.
 * All the Sinnoh starter's evolved forms (Torterra, Infernape, Empoleon) can be super effective to each other with their secondary typing.
 * HeartGold and SoulSilver were released packaged with a pedometer called a PokéWalker that allows players to carry their Pokémon with them.
 * All the Sinnoh starter final evolutions can learn the move Earthquake.
 * Generation IV has the most Legendary Pokémon of any generation.
 * Generation IV has the most evolutionary additions to previous Generation families, such as Sneasel and Weavile or Tangela and Tangrowth.
 * Inventions from Generations IV and V were hinted in the third generation games, Sapphire, Ruby, and Emerald. If you go to the Devon Corporation building,on the second floor you see various scientist working on computers. When you talk to the scientists, one states that he is working on a device that will revive Pokémon fossils he follows by stating its working. When you talk to the other scientist on the computer he states that he is working on a device that will visually reproduce the dreams of Pokémon and he follows by stating that it is not going well. If you talk to the last scientist on a computer he will say he is developing a device that will allow you to talk with Pokémon he follows by saying that he hasn't had much success. The last invention could possibly show up in Generation VI.
 * In Platinum, Fantina is the third Gym Leader. Maylene is fourth and Crasher Wake comes fifth.
 * This is the first Generation to have online Pokémon battles.