When Aria was nineteen, they went to study at the Bangkok Institute. Aria began introducing David as Diana, allowing her to be herself. One day, the siblings went exploring a group of islands rumored to have demons; what they found were revenants. In the ensuing battle, Aria was fatally injured and she died shortly after, despite attempts by Catarina Loss to treat her. Diana, heartbroken, survived and assumed her sister's place after their parents falsely reported to the Clave that David had died instead of Aria.
Aria was a very accepting and understanding person. She was also very perceptive, as she was able to determine on her own that her sister was a woman without being told.