The term SCI-FI CHARACTERS can refer to a variety of characters from science fiction literature, films, and television shows. Two of the most common characters are ALIENS (6 letters) and ETS (3 letters). ALIENS are typically extraterrestrial creatures that come from other planets or galaxies, while ETS are often humanoid ALIENS with advanced technology and abilities. Both types of characters often have a mysterious and unknown origin, and are used to explore themes of exploration, discovery, and the unknown.