The fifth gym leader is Fantina and she uses Ghost Pokemon. No element is strong against ghost except ghost, so just use your strongest Pokemon. But be careful - ghost to ghost is super powerful, but unless your ghost Pokemon is a much higher level than hers, do not use it since her attacks will be super effective against you. The best Pokemon to have are just a well-rounded team with most of the elements covered.
The 5th Gym Badge is in Pastoria. You have to beat Crasher Wake which you met when you were going to the 4th gym. He specialises in water Pokemon. He has Gyrados, Quagsire and Floatzel. They are all in the mid 30's. The best type of Pokemon to use against Gyrados is an electric Pokemon. Against Quagsire you should use a grass Pokemon. On Floatzel you could use either grass or electric Pokemon.
the best Pokemon to pick at the start is PIPLUP or CHIMCHAR
You can find the bestest,rarest, Pokemon is to go to www.marriland.com/pokemon
=====================DARKRAI===========
ash and pole
Diamond is not a Pokemon but i think Arceus is one of the strongest Pokemon ever.
the best Pokemon on diamond would be arceus but you can only get that from action replay, other than that i think the best Pokemon would be giritina..
the best Pokemon for the Pokemon league is definetly latios
Palkia
the best Pokemon in diamond is arceus, but you have to use action replay or wi-fi mystery gift
No Arceus is the best Pokemon in Pokémon Diamond.
The 5th Gym Badge is in Pastoria. You have to beat Crasher Wake which you met when you were going to the 4th gym. He specialises in water Pokemon. He has Gyrados, Quagsire and Floatzel. They are all in the mid 30's. The best type of Pokemon to use against Gyrados is an electric Pokemon. Against Quagsire you should use a grass Pokemon. On Floatzel you could use either grass or electric Pokemon.
The best Pokemon on Pokemon diamond is obviously a Bidoof...Joke :)No this is entirley an opinion based question but the best aka most powerful,and most defensive is Diagla
Chimchar
a lot of legendary Pokemon
swampert miltic
the best Pokemon to pick at the start is PIPLUP or CHIMCHAR