Emilia, known as Emelia in the manga, is an actress who works at William's theatre.
Emilia has fallen in love with Juliet's disguise as a boy, Odin. It's because of this that Romeo and Juliet meet: Emilia is invited to the Rose Ball, but she doesn't want to go alone, fearing it will make her look bad. She takes "Odin" along with her, telling "him" to dress up as a girl, allowing Juliet to dress freely for the first time.
Emilia is one of the last chararcters to discover "Odin" is really Juliet.
Emilia is talented and bright, but loud and demanding of those around her, determined to get what she wants. Despite this, she is shown to be warm and a good friend when it's needed the most.