Initially highly closeted to herself, Alex is the adoptive older sister of Kara, aka Supergirl. Working for the DEO, she protects the world from extra-terrestrials. After seriously crushing on Maggie Sawyer, Alex came out to herself and then Kara, and finally everyone. Alex and Maggie dated and were briefly engaged until they hit a wall over wanting to have kids issues.
(Olivia Nikkanen plays a young version of Alex in Supergirl.)