No
In pokemon diamond and pearl
maylene
water
NO retard
he is only in diamond or pearl or platinum.
She's the gym leader of Hearthome City and an user of ghost Pokemon.
By beating the gym leader
Byron (as Roark's Dad.) He is the 6th Gym leader in Diamond, Pearl, and Platinum. Also his Pokemon is Steel type.
There is no way to really become a leader in pokemon. With AR you might be able to stand in as a leader, but you are never a real leader, and it is impossible without AR.
Brock isn't in Diamond and Pearl. He is in another game but i forgot which one it was. Hes in Pokemon LeafGreen and FireRed as the frist gym leader and there he got geodude and onix
Candice
trade diamond from Pokemon diamond onto Pokemon pearl