Aura

Aura (Japanese: 波導 Hadou, literally Wave Guidance) is a metaphysical concept introduced in Lucario and the Mystery of Mew. It is described as the living essence inside of every living creature.

In the Pokémon world's past, there were once humans that could sense and control its power. These humans, known as Aura Guardians, travelled around doing good deeds and passing on their skills to those who also possessed this inate ability. One famous Aura Guardian was Sir Aaron who took a Lucario as his apprentice and became a hero when he sacrificed himself to stop a war from destroying the area around the Tree of Beginning. In DP056, the group heard the story of how a Spiritomb was sealed away by an Aura Guardian who travelled with a Pikachu.

The Aura Guardians disappeared from history for some undisclosed reason a long time before the present era. The only human in the present known to have the ability to control aura is Ash Ketchum and he has chosen to continue his journey as a Pokémon Trainer rather than follow up on the revelation. However, he did follow in the footsteps of both Aura Guardians by helping Lucario to save the Tree of Beginning and resealing Spiritomb.

Aura also plays a minor role in the Gamecube RPGs. The process that creates Shadow Pokémon surrounds them with a darker aura that, while still invisible to most people, can be seen by Rui of Pokémon Colosseum. By the time of Pokémon XD: Gale of Darkness, the Aura Reader had been developed to automatically identify this aura for those that can't normally see it.