Like Pokémon Diamond & Pearl, Pokémon Platinum contains the unused Azure Flute item, which triggers a battle with a level 80 Arceus in the otherwise inaccessible Hall of Origin atop Spear Pillar. The event is almost identical to how it appears in Diamond & Pearl, with the sole difference being a redesigned sprite for Arceus. The Azure Flute was intended to be given out to players as an event item, but was scrapped due to concerns that it would be too confusing for players. Instead, Arceus was directly given out as an event Pokémon.

The music for the Hall of Origin and the battle against Arceus, which are carried over from Diamond and Pearl, go unused here too, but the latter song would be reused for the Sinjoh Ruins event in Pokémon Heart Gold & Soul Silver, where players can obtain a Dialga, Palkia, or Giratina if they have an Arceus at the front of their party. This event additionally contains code allowing it to be triggered by an Arceus from the Hall of Origin, indicating that Game Freak still considered distributing the Azure Flute this late into Generation IV. Spoiler:The Azure Flute and Hall of Origin would eventually be implemented in Pokémon Brilliant Diamond & Shining Pearl, where players can access both if they import Pokémon Legends: Arceus save data after catching Arceus there.