The Aura is an animation for when the Pokémon boost reach 50.
There are 3 types of aura:
1. Common Aura: You can purchase a common aura in the NPC Shurya in Gary's Lab, with the following dialog:
'hi, change aura, yes, name of the aura'.
2. Urn's Aura: Urn are items that can be get in drops in game, when used in the Pokémon, change your aura to the one contained on the Urn.
3. Particle Aura: You can buy it on the Diamond Shop and can change it at any time with de command: !particle