one of the three johto starters: totadile, cintaquil or chikorita
You have to catch 151 pokemon to complete the pokedex.
You get the Pokedex after choosing your starter Pokemon in Prof. Birch's lab.
He Just Gives you a Certificate that shows that you have completed the Pokedex. Thats All He Does.
catch all Pokemon
It is grimer
The original Pokedex is given to the player by Professor Birch. After the Pokemon Ruby trades with LeafGreen or FireRed the National Pokedex will be unlocked.
beat the hoenn pokedex and go to prof.birch
Just a certificate saying that you completed the pokedex.
http://pokemondb.net/pokedex/national
Okay, to get the Pokemon to fill the National Pokedex, either you: migrate Pokemon from Emerald, Ruby, Sapphire, Firered, and Leafgreen. Or you could go in the wild near thesurvival area, which won't help a lot but it can help. Hope this helps!!
If you have completed the whole game, you well have every Pokemon in your pokedex (Encluding the ones you get after the National Pokedex) and you will have battled everyone and completed the Pokemon Leadge. You will also have the black Trainers Card.
www.serebii.net/pokedex-rs/