Cataleya is a young woman who has grown up to be an assassin after witnessing the murder of her parents as a child. Turning herself into a professional killer and working for her uncle, she remains focused on her ultimate goal: to hunt down and get revenge on the mobster responsible for her parents' deaths. Vartan was born in Boulogne-Billancourt, Hauts-de-Seine, France, the son of Doris (née Pucher), a painter and artist, and Eddie Vartan, a musician. His paternal aunt is singer Sylvie Vartan and his stepfather is writer Ian La Frenais. Vartan's Bulgarian born father was of Armenian, Bulgarian, and Hungarian ancestry. and Vartan's American mother is Jewish and originally from Poland. Vartan has said about his French background that "The funny thing is I'm actually a Polish Jew who happens to be born in France. My mom is Polish and my dad is Bulgarian. I don't have an ounce of French blood. But I work it". He has stated that he tends to be considered a Frenchman in the United States and an American in France.
His parents divorced when he was five and he moved to America with his mother. He moved back to France to be with his father until his high school years, and grew up a "farm kid" in a "simple environment" in Fleury, Manche, a small town in Normandy. At the age of eighteen, Vartan moved back in with his mother in Los Angeles, telling her that he wanted to be an artist, because he did not wish to fulfill the mandatory military service required in France. In Los Angeles, he attended an acting school after he was told he possessed acting talent. He had also attended the prestigious Lycée Français de Los Angeles. Vartan now considers himself to be American and stated on the talk show Rove that he would like Australia to be his second home. He is bilingual, speaking both English and French fluently.