Lieutenant Ellen Ripley is the main protagonist in the first four Alien movies, and one of the first female action heroes in film. Ripley is played by Sigourney Weaver, who delivered a character that is intelligent, confident, adaptable, and able to overcome sheer terror to stay alive. She was nominated for an Academy Award for Aliens, a significant achievement given how little science fiction or horror are acknowledged by the Oscars.

The character was originally planned to be male, but director Ridley Scott chose to make the character a woman instead. Casting a woman as the lead hero made Alien a revolutionary movie within science fiction and action genres. Those types of movies usually cast woman as supporting characters or damsels for the male hero to save, but in Alien, Ripley went through a brutal fight with the villain and survived.

Ripley was introduced in 1979’s Alien as the warrant officer on the spaceship Nostromo. When the crew investigates a nearby planet, they unwittingly bring an unknown creature onboard, despite Ripley’s warning not to let an infected crewmate back on the ship. One by one, the Alien kills the rest of the crew, leaving Ripley alone to kill the creature while fleeing the ship.

She returned in 1986 in Aliens. Set 57 years after the first movie, Ripley wakes from stasis to learn that a colony was set up on the planet where her crew found the alien eggs. When the colonists stop communicating, she joins a military operation to investigate the situation where they quickly discover that everyone is missing. Despite being heavily armed, the marines are killed by multiple Aliens, and the movie culminates in a battle between Ripley and the Alien Queen.

Alien 3 came out in ’92, with Ripley crash landing on a penal colony. An alien egg was aboard the ship she had fled in, and as soon as the Alien hatches, it starts killing the inmates and guards. Ripley discovers that the Alien Queen had planted an embryo inside of her, so she kills the Alien through thermal shock and then throws herself into a furnace as the new Alien Queen starts to burst from her chest.

Weaver had her last live-action onscreen role as Ripley in 1997’s Alien Resurrection. Set 200 years after Ripley died, she is cloned and scientists extract the Alien Queen embryo from her body. The United Systems Military plan to breed Aliens by implanting them in kidnapped hosts. When the plan goes awry, the Ripley clone leads a group of mercenaries to destroy the Xenomorphs before they land on Earth.

Ripley has been in many other Alien projects outside of Weaver’s portrayal in the first four movies. She has starred in comic book series, like Alien: The Illustrated Story (1980) from Heavy Metal, and Aliens (1988), Alien 3 (1992), and Aliens vs. Predator vs The Terminator (2000) from Dark Horse Comics. Ripley has been in at least a dozen novels, including novelizations of the films. She has also appeared in video games, dating back to the 1990 Aliens arcade game, and Weaver did a voice cameo for the Alien: Isolation video game that came out in 2014.