Sydney is depicted in the series as being strong both physically and emotionally. She deals with some significant trauma over the years: the death of her fiancé, the death of her best friend, the realization that her mother was a former KGB spy, the estrangement of many of her friends and the constant activity and changes that she must endure from being a spy on a regular basis. Sydney is highly skilled in Krav Maga and is quite a polyglot, speaking English, Russian, German, Greek, Dutch, French, Italian, Spanish, Portuguese, Norwegian, Swedish, Romanian, Hungarian, Hebrew, Uzbek, Arabic, Farsi, Urdu, Indonesian, Cantonese, Mandarin, Japanese, Korean, Hindi, Vietnamese, Polish, Serbian, Czech, Ukrainian, and Bulgarian in various episodes. Throughout the series her code names were bluebird, freelancer, mountaineer, and phoenix.