I always choose the grass starter. Though most say they are the weakest, They level up quickly. Later in the game, There are very strong water and fire type pokemon, but not very many good grass type. So if you get he grass starter that won't be an issue.
But that's only my opinion :)
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In Pokemon Gold/Silver/HeartGold/SoulSilver - Definitely Totodile. His final evolution form has high attack and high defense. And if you're playing HeartGold/SoulSilver, it will learn Superpower too.
In Pokemon Ruby/Sapphire - Torchic is the best choice. Its final evolution form - Blaziken has amazing moves like Blaze Kick, Sky Uppercut, Slash, Double Kick and more. And its extra fighting type covers its weakness to rock type.
In Pokemon Blue/Red - Definitely Charmander. His attack is the highest out of Squirtle and Bulbasaur. His defense may be low but his high attack can finish the foe before he dies.
In Pokemon Pearl/Diamond - Piplup is the best starter. Its final evolution form - Empoleon is strong. Its extra steel type decrease the super effective damage from lightning type to water type. And it can learn some good moves too. Like Drill Peck, Hydro Pump, Avalanche, Hyper Beam, Giga Impact and many more. What's more if you want to teach him HM moves, well he can learn all of them except HM02 Fly.
mew
it depends on what Pokemon type u want to faint
by starting a new one and saving over it
The safari area
I think arceus is the the strongest Pokemon in diamond and pearl. Also no moves are supereffective on Spiritomb and arceus
IT IS NOT IN POKEMON DIAMOND OR PEARL BECAUSE IT IS ONE OF THE STARTING POKEMON IN LEAFGREEN!!!!! Migrate one from firered or leafgreen.
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.
sorry but you have to get another diamond/pearl/platinum game and trade the other starters from there.
no, you have to trade w/ GTS
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