in lake valor after you have caught Giratina and talked to prof. rowan in sandgem
Chat with our AI personalities
They will run away, and you have to find them in the wild and capture them.
You have to search around and find them in grass somewhere, across the whole map
The rare Pokemon which you can get before the Elite Four in Pokemon Platinum are Giratina, Mesprit, Uxie, and Azelf.
in platinum the different sprites are UXIE,MESPRIT and AZELF
You can't, you will need to trade them from Pokemon Diamond, Pearl or Platinum.