If you're asking about the protagonist of 'The Bourne Legacy', it can get a bit confusing because the name is shared, but the character is entirely different from the one in the original trilogy. The novel, written by Eric Van Lustbader who continued Robert Ludlum's series, actually follows a new main character named David Webb. Now, Webb is still Jason Bourne—or rather, he is the man who used to be Bourne, trying to live a quiet life. But the story really centers on him being pulled back into that world, so he is very much the central figure through whose eyes we experience the conspiracy and action. The legacy in the title refers more to the lingering consequences of his past actions and the programs that created him, not to a new, separate hero taking up the mantle.
So, unlike the film adaptation which introduced Aaron Cross as a parallel operative, the book sticks with the original Jason Bourne character, just under immense new pressure. The narrative digs into his struggle to protect his family while dismantling a global threat that feels like a direct result of his own history. You're following his strategies, his internal conflicts, and his relentless pace as he navigates a web of assassins and secret agencies. It’s a return to the core of who he is, even as he fights to leave that identity behind, which creates a fascinating tension throughout the entire plot. I always found Lustbader’s take on Webb’s weariness and relentless skill to be a compelling extension of the character Ludlum built.