The male protagonist of the story. He is the eldest son of the "House of Jones." a very wealthy merchant middle class family that is attempting to rise into the gentry. As his father's heir, he is under tremendous stress to not only take over the family business but also marry a girl from another wealthy family, preferably into the peerage. He developed feelings for Emma after their first meeting. He often intercepts her coming from Covent Garden on Regent Street. In the manga, William had told his father about Emma but his father had never seen Emma (different with the anime).
After Emma's departure, William changed drastically. He began to work very hard, attending social meetings and took care of his family's business. In his own perspectives, he never stopped regretting losing Emma, but he would live his life in the 'upper class side' as his father expected him to be. His change affected everyone around him, including Hakim.