I am not sure how to catch darkrai or creselia but to obtain Palkia or Dialga you have to go to Spear Pillar in mount Cornet.
the legendary Pokemon in diamond and pearl are dialga and palkia.
Palkia is the legendary Pokemon in Pearl, and there is also various Pokemon found in Pearl, but not in Diamond. Diamond has some, that Pearl doesn't have.
you have to take it from Pokemon fire red or leaf green...they are not actually in the storyline for Pokemon diamond and pearl
Two legendary Pokemon from Pokemon diamond, pearl and platinum.
Migrate it.
Empoleon is not a legendary Pokemon. It is the final evolution of Piplup, one of the starter Pokemon in Pokemon Diamond, Pearl, and Platinum.
there are 150 kinds of Pokemon that you can see and/or obtain. Unless you have friend trade you Pokemon that you can only get in pearl to you, you'll never obtain them all. In Pokemon diamond and pearl all you have to do is see the Pokemon and you get its data unlike the older versions where you have to obtain them.
Not much. Pokemon diamond and Pokemon pearl have different Pokemon. for example, in pearl you can catch a glameow but not a cranidos and in diamond you can catch a cranidos but not a gleameow. And at the end of pearl you can catch Palkia the legendary and at the end of Diamond you can catch Diagla. But the games are basically the same. And there you go.....
darkrai and arcus
You'll have to have received it from a special event.
No. You need codes and a friend who has pearl. (and Pokemon ranger) or YOU could have Pokemon pearl and Pokemon ranger not just your friends.
Milktank is located in route 209 and 210 in both Diamond and Pearl.