The complete Pokemon Diamond and Pearl pokedex, part 9

Pokémon Name: Dialga
Type: Dragon / Steel
Classification: Time
Pokédex Number: 483 National
Ability: Pressure – Opponent uses 2 PP when attacking
Dream World ability: Telepathy – Always avoids damage from teammates' moves in double and triple battles
Useful Attacks: Roar of Time
Location Found:
Diamond/Platinum: Spear Pillar
Pearl: Trade with Diamond/Platinum
HG/SS: Sinjoh Ruins while event Arceus is the only Pokemon in your party
B/W: Poke Transfer

Dialga is Pokémon Diamond's covermonster. Dialga's revived by Team Galactic with the aim of using its power over time itself to restart the universe, and is stopped by Sinnoh's trio of guardian spirits. Dialga's type combination protects it from its susceptibility to both of the Dragon type's Ice and Dragon weaknesses, but opens it up to two more common types, Fighting and Ground. Dialga's signature move, Roar of Time, is more powerful at face value, but leaves Dialga immobile the following turn, making its use risky.