Jack's arc as an uber-powerful Biotic who can become one of your most trusted companions is a masterstroke of writing and game design, but you might have completely ignored her thanks to an introductory sequence that paints a picture of at any moment your ship being imploded by a single thought. Still, if you scratched away at that surface layer built up from years of isolation and rejection, the hard-edged warrior could become an extremely loveable and trustworthy companion. She's all but missing from part three regardless of your interactions beforehand, and depending on your feministic frequency you might hate the idea that the 'reformed' Jack is more in line with a 'hot biker chick' aesthetic than as an extension from what she was in part two. Regardless, Jack has Star Destroyer-felling levels of power at her finger tips, and in the exploration of all things that are universe-altering, she could be the linchpin for a major upcoming story arc.