Once the Elite Four are defeated and the player has found both the Adamant and Lustrous Orbs in Mt. Coronet, Cynthia's grandmother will tell the player that in ancient times, people apparently met with Dialga and Palkia, by having the Adamant and Lustrous Orbs. Returning to the Spear Pillar with these items, the player will be able to battle with and potentially capture Dialga and Palkia.