kill the elite 4 noob
There is are no certain Pokemon needed to defeat the elite four. Just use your strongest Pokemon.
You have to deafeat the elite four and go on the S.S. Tidal.
You can find out how many times you have beaten the Elite Four in Pokemon Diamond by checking your PC in the game.
it is the elite four
nation pokedex
The champion in the Elite Four.
defeat the elite four
-mongmong908
In the Pokemon games, the Elite Four are kind of the final boss to the games. In every game (including Pokemon Diamond) you will find them at the end of Victory Road.
the same
Beat Cynthia after Elite Four
erm......you battle them.