On the Trail of Giratina

Unlock Criteria: Defeat Volo in the Temple of Sinnoh

Description: A huge shadow has been seen in the Cobalt Coastlands. According to Professor Laventon, there's a strong chance it is Giratina, the fearsome Pokémon you once battled.

After you have defeated Volo at the Temple of Sinnoh, Professor Laventon will tell you of a shadow that has enveloped the Cobalt Coastlands. If you head to the Spring Path in the north west, you will find the Legendary Pokémon Giratina in its Origin Forme in the middle of the cave. Catch it and you will then get the Griseous Core so it can change forms