Aria, originally named Volo in her world of Hisui, is a female version of Volo. Just like the male Volo, in her world, Arceus chose Akari instead, and Akari got the Azure Flute instead of Aria. In Aria's eyes, Akari did not deserve that right, not the attention from Arceus. After learning the secret of time travel by using the Green Stone, which supposedly harnesses Celebi’s power, Aria used it to figure out where Akari’s real world reincarnation, Grace, lived, and travelled to that world.