Overview
Alexandra Rousseau is a fictional character on the ABC television series Lost played by Tania Raymonde. She was born 16 years prior to the crash of Oceanic Flight 815, but was taken from her mother, Danielle Rousseau, by Ben Linus. She was raised among them, believing her mother to be dead. She has helped the survivors of Oceanic Flight 815 on many occasions, and is reunited with her mother at the end of the third season. Not long after however, she is shot and killed by Keamy after her adoptive father, Ben, would not listen to his demands. Her death scene was received positively by critics, earning it a spot on multiple "top moments of the season" lists.
Arc
Before the crash
A heavily pregnant Danielle Rousseau (Mira Furlan) and her husband Robert (Guillaume Dabinpons) along with the rest of their crew, shipwrecked on the island, 16 years before the crash of Oceanic Flight 815, during a French scientific expedition. According to Rousseau, her team becomes "sick", so she kills them all, and later gives birth to Alexandra. Rousseau claims she saw a column of black smoke on the island a week later. That night, Benjamin Linus (Michael Emerson) and a young Ethan Rom (William Mapother) are ordered by Charles Widmore (Alan Dale) to kill Danielle and, subsequently, her baby, Alex. Instead, unwilling to kill an innocent child, Ben neglected Widmore's orders and kidnapped Alex to raise her as his daughter and let Danielle live.
After the crash
Sixteen years later, Alex meets the pregnant woman Claire Littleton (Emilie de Ravin), whom the Other, Ethan Rom, had kidnapped to take her baby. Alex tells her that the Others will kill Claire once they get her baby. She leads Claire out of the Others' hatch and tries to make her get back to safety.
From Wikipedia (CC BY-SA 4.0).