Well you Must find all Pokemon in Sinnoh. Then go to prof rowans lab in sandgem and he will give it to you o and if he doesn't then that means you didn't talk to your friend that was outside of the lab ( in sandgem where prof rowen is)
he will to you to go some where and the place where he tells you to go is where the old lady will show you Pelkia or Dialga matters what game you have and ya that's it.!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!^_^ =]
Arceus
Garatina...
in the national pokedex: arceas in the regular pokedex: dialga
if you meen the national dex then you need to find every Pokemon in the sinnoh pokedex
THE LAST FIVE POKEMON IN THE POKEDEX IN DIAMOND IS UXIE MESPRIT AZELF DIALGA AND PALKIA. NOTE: PALKIA CANT BE CAUGHT UNLESS YOU TRADE WITH SOMEONE.
Palkia, the one on the cover of Pearl.
No, there is not a Pokedex after the National Pokedex in Pokemon Diamond Version.
diamond pokedex number 80 is Barboach
Riolu
Oddish is the 43rd Pokemon.
in the national pokedex it is mackoke. if it is in the sinnoh pokedex it is buneary.
Number 33 is Golem on the Sinnoh Pokedex.