Spear Pillar (Japanese: やりのはしらSpear Pillar) is a location in Sinnoh where the ancient Pokémon Dialga, Palkia, and Giratina were created by Arceus and from which, legends say, Sinnoh itself came from.
The area is located at the very peak of Mt. Coronet, and is the ultimate goal of Team Galactic's plot. It is here that Cyrus summons both Dialga and Palkia to claim their powers and create a new universe for himself, free of emotion (though he only manages to summon one of the pair in either Diamond or Pearl, and its power is partly neutralized by the lake guardians before the player battles Cyrus). Mars and Jupiter battle against the player and their rival, standing in the way before the player's challenge against Cyrus.
If the player has the Azure Flute on returning to Spear Pillar after capturing all of the creation trio, as well as having the National Pokédex, blowing into it will cause a staircase leading to the Hall of Origin to appear. It is an event-only area, and when the player has the Azure Flute and returns to Spear Pillar after defeating the Elite Four (as the event will not be possible until after Team Galactic has been vanquished and Dialga, Palkia, or Giratina has been captured, defeated or fled from), the flute will make a sound. After blowing into the flute, a staircase will appear leading up, out of sight. After reaching the top of the staircase, the player attempts to capture the legendary Pokémon, Arceus.