Probably Arceus. He has the highest Base Stat Total of any pokemon, he can be any type, and he has a giant movepool. But he can only be gotten through events (or hacking)
Other than that, maybe Kyogre. His rain boosted water spout can do extreme amounts of damage, killing basically everything that doesn't resist it (except Blissy)
The Frontier Brains and the Champions.
Raiku the electric dog on leaf green and fire red versions
The rival the third time you battle him in survival area
The strongest Pokemon in Platinum is probably Arceus, to get Arceus, you need a mystery event, but that event is finished now. :( The second strongest Pokemon would probably have to be Giratina, or probably dialga or palkia.
mew is the strongest Pokemon
Giratina
There isn't one.You can train well,and any Pokemon can be the strongest.But there really is not a strongest Pokemon.
no one nows
The easyest Pokemon is scizer and the hardest Pokemon is milotic.
The Frontier Brains and the Champions.
when you battle Pokemon champion Cynthia in Pokemon pearl,platinum,and diamond her strongest Pokemon is garchomp
In my opinion torterra is the strongest Pokemon. In order for this Pokemon to be the strongest, it must know these four moves: Frenzy Plant Earthquake Crunch Giga Drain
The strongest Pokemon I met is a 100 lvl Magikarp in Resort Area(I call it King Magikarp :D )
Raiku the electric dog on leaf green and fire red versions
arceus is i said party not single pokemon.
It all depends on the level and the moves it knows.
The rival the third time you battle him in survival area