Well, Idk what kind of pokemon you have but, I can tell you what pokemon the champion has.
Spiritomb Lv 61
Lucario Lv 63
Gastrodon Lv 60
Garchomp Lv. 66
Roserade Lv. 60
Toughest of All: Milotic Lv 63
Beat everybody else.
beat the elite 4 then champion Cynthia
yeah you can
beat the elite four and become champion
u cant without an action replay
Cynthia is the Champion so you will see her when you beat the Elite Four
i don't really know but try spear pillar after you beat the Pokemon champion I beat the Pokemon champion but I wasn't up there since Palkia team galactic was there so try spear pillar okay try spear pillar.
The champion is Pokemon Diamond, Pearl and Platinum, is Cynthia. She has various Pokemon-types. She is the Sinnoh Champion. Her Pokemon are Spiritomb, Lucario, Togekiss, Milotic, Garchomp and Roserade. In Platinum, Cynthia has a Togekiss. In Diamond and Pearl, she has a Gastrodon.
you beat the champion
You have to beat the original champion in the game
beat the elite four and the champion.
You need to beat the elite four and then beat the Pokemon league champion