Cassie Sandsmark, also known by her superhero alter ego Wonder Girl, is a young girl of 15 with blond hair and blue eyes. She has boundless energy which she's either using to help people or trying to understand the members of her team. She's usually very cheerful and up beat, though once Wonder Girl kicks in, she's all buisness.
-Her Wonder Girl costume:
-one black tank top with the Wonder 'W'
-one black sleeveless pullover with the Wonder 'W'
-one pair white skating goggles
-two silver arm guards
-one pair red jeans with white stars down the legs with a black belt
-one red sports bra and matching red underwear
-one pair heavy duty black boots with white socks
-Two hair ties in the pocket of her jeans
-One commlink clipped over her ear and hidden by her hair
-One silver chain with a round plate that says "Girl" flanked by a bead on either side
Cassie arrives on the island after the end of the series Young Justice but before the three part crossover with the Titans Graduation Day