Aya Brea is a rookie cop for the NYPD. Aya was drawn to a newspaper advertisement for an opera on Christmas Eve of 1997. There, she witnessed the audience burn to death as the female lead of the opera, Melissa Piece, agitated each individuals mitochondria, causing each person to spontaneously combust. Aya Brea shunted her date, who fell to the ground, as he tried to flee. Aya learned that her nucleus was being given extra power by her mitochondria, allowing it to withstand Melissa Piece's psychic-mitochondrial onslaught.
She is voiced by Yvonne Strahovski in the English version of The 3rd Birthday and is voiced by Maaya Sakamoto in the Japanese version.