Kara's adoptive sister. She is a doctor and scientist who works for Hank Henshaw at the DEO. Having been extensively trained in combat after joining the DEO, Alex in turn provided rigorous training to Kara in order to decrease her reliance on her powers. Initially, like Kara, she becomes suspicious of the DEO and thus her own role upon learning of their father having worked there in order to protect Kara, but Alex ultimately learns that Henshaw is the Martian survivor J'onn J'onzz in shape-shifted disguise, whom her late father had rescued before his and the real Henshaw's deaths. Jordan Mazarati plays a young Alex. In season two, Alex continues to search for her father, while she meets and befriends Maggie Sawyer. She develops feelings for her, forcing Alex to confront her sexuality.