Even though she's only twenty-six years old, Luisa Rey is a timeless hero: she's an intrepid journalist fighting corporate greed. She's timeless because we always need a hero, and there will always be corporate greed, so there will always need to be someone to stand up for the little guy.
Luisa doesn't just stand up for the little guy; she gets knocked down repeatedly and stands up every time, stronger and stronger. Here's just a taste of what happens to Luisa: her car gets rammed off a bridge (with her in it), a bank blows up (with her in it), and an armed psychopath boards a yacht (with—you guessed it—her in it). Would you go through all that for a newspaper article? What if hundreds, if not thousands of strangers' lives were in jeopardy?
It's no coincidence that Rufus Sixsmith feels like he's known Luisa for years. She shares many qualities with Robert Frobisher, but they're just as different as they are similar. Let's split-screen the two and compare, shall we?
1) Luisa has daddy issues of a different kind from Frobisher's. Whereas Frobisher's Pater is cold and oppressive, Luisa's father, Lester, is a heroic cop and a stellar journalist. He gives Luisa huge shoes to fill: Luisa says, "What kind of a mockery of his life would it be if his daughter bailed when things got a little tough?" (3.6.12). We doubt she'd be as fearless as she is if it were not for the influence of her father. (We do, however, feel the need to give a Worst Mom shout-out to Luisa's ma for trying to set Luisa up on a blind date with Bill Smoke, the man who has been trying to murder her. Great going, Mom.)
2) Luisa has no problems with rejection. She's a journalist. Rejection is part of the job.
3) Luisa's a disgruntled employee, not just of Spyglass magazine, but of society in general, a society where "[corporations] can extinguish awareness by dumbing down education, owning TV stations, paying 'guest fees' to leader writers, or just buying the media up" (3.26.1). Buying the media up to silence Luisa is exactly what Seaboard Corp. does, but she doesn't give in; she fights back.
4) Luisa is so not a romantic. She doesn't believe in any of that reincarnation bull-honky. When she finds out that Frobisher had the exact same birthmark she does, she talks herself out of it: "Coincidences happen all the time" (3.24.26). But she still feels the undeniable pull of the past: the Cloud Atlas Sextet sounds eerily familiar to her, and she's inexplicably drawn to the story of the Prophetess.
5) If genius means figuring out something no one else can figure out then, yep, Luisa's a genius. Even her editor, Dom Grelsch, is initially skeptical of her theories, and he makes fun of her by saying, "So, […] everyone got it wrong except Luisa Rey, ace cub reporter" (3.21.19). How does Luisa react to this? She just persists and solves the case.
6) Luisa is fated not to die. Why? Well, she might just be a fictional character. (Yes, we know Cloud Atlas is a work of fiction, but Luisa might be fictional within the world of the novel.) Her section of the novel, Half-Lives, appears in Timothy Cavendish's section as a work of fiction. However, Cavendish has this to say about the work: "Half-Lives—lousy name for a work of fiction" (4.1.97). Could Half-Lives be fact masquerading as fiction, like Primary Colors or that weird Obama novel? And if Luisa's fictional, does that invalidate everything she stands for?